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Regulation and Impervious Surfaces: A Case Study Looking at Changes in Total Impervious Area (TIA) and Impervious Surface Regulations for the Blake Lake Region
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Creator (dcterms:creator)
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Adair, Celinda
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Date (dcterms:date)
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2007
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Subject (dcterms:subject)
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Environmental Studies
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extracted text (extracttext:extracted_text)
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Regulation and Impervious Surfaces: A Case Study Looking at Changes in
Total Impervious Area (TIA) and Impervious Surface
Regulations for the Black Lake Region
By
Celinda Adair
A Thesis: Essay of Distinction
Submitted in partial fulfillment
of the requirements for the degree
Master of Environmental Studies
The Evergreen State College
June 2007
1
This Thesis for the Master of Environmental Studies Degree
by
Celinda Adair
has been approved for
The Evergreen State College
by
_________________________
Paul R. Butler
________________________
Date
2
Abstract
This thesis establishes a process for evaluating regulatory effectiveness,
using total impervious area data in combination with an implementation timeline
for relevant land-use regulations. The findings determine that such evaluation is
possible and has multiple benefits. A case-study was done for the Black Lake
region of Thurston County Washington. An analysis of total impervious area was
done for Black Lake’s 200 foot shoreland region for eight different years over a
68 year time span. An implementation timeline for relevant land-use regulations
was created and used in combination with the total impervious area data to
measure regulatory effectiveness. The primary regulations evaluated are the State
Growth Management Act (1990) and Shoreline Management Act (1972), that
mandate Thurston County adopt land-use regulations pertaining to impervious
surfaces. The two primary Thurston County regulations evaluated in this casestudy are the Comprehensive Plan (1995) and Shoreline Master Program (1976).
The results of the case-study analysis determined that neither set of regulations
have effectively slowed the rate of increase in impervious areas within the case
study region.
3
Acknowledgment
Some say it takes a village to raise a child; well in this case it took a small
army of truly wonderful people to make the completion of this thesis possible.
Thank you, Alexis, for inspiring me to do my best, no matter how difficult things
got and for sacrificing playtime so that mommy could get her work done. Thank
you, Sofia, for motivating me to complete this thesis, even if I didn’t get it done
until after you greeted the world. Thank you, Paul Butler, for your ingenuity,
flexibility, and for having faith in me during this long process. Most of all thanks
goes to my husband Nick and my parents Jim C. Rupp-Ramsey and M. Jeanie
Ramsey for your willingness to provide endless amounts of support,
encouragement, and self-sacrifice, in order to allow me to follow my dreams.
Many friends and colleagues have also provided never-ending support
over the last two years. Cinde Donoghue: thank you for your help with
formulating and editing; Amy Calahan: thanks for your help locating data and
everything else; Sarah Haque: thanks for motivating me when I was running low
on drive; John Pumilio: thanks for your help refining things and your camaraderie
throughout this process; and Jessica Moore and Maurice: thanks for always
having a sense of humor when I needed it. A final thank you goes to the many
other people whom I have not named, who provided support during the process of
writing this thesis.
4
Table of Contents
List of Figures
List of Tables
Acknowledgment
Page #
v
vi
vii
Chapter 1: Introduction
1
Chapter 2: The Effects of Impervious Surfaces on Ecosystems
6
Chapter 3: Policy Analysis
Overview
General Background
Shoreline Management Act: Background Information
Shoreline Master Programs
Requirements for the Shoreline Management Act’s Purview to
be Applied
Thurston County’s Shoreline Master Program – Goals, Policies,
and Objectives Relating to Impervious Surfaces
The Growth Management Act: Background Information
The Growth Management Act’s Planning Goals
The Growth Management Act: How it Applies to the Study
Area – Overview
Thurston County Comprehensive Plan – Goals, Policies, and
Objectives Relating to Impervious Surfaces
Urban Growth Areas and Joint Plans
City of Tumwater and Thurston County Joint Plan – Goals,
Policies, and Objectives Relating to Impervious Surfaces
Development Regulations
Zoning Regulations
Critical Area Ordinances
Thurston County’s Critical Area Ordinance – Goals, Policies,
and Objectives Relating to Impervious Surfaces
Thurston County’s Drainage Design and Erosion Control
Manual – Goals, Policies, and Objectives Relating to
Impervious Surfaces
10
11
12
12
13
14
15
16
17
17
18
19
20
21
21
22
23
Chapter 4: Case-Study – Overview
Characteristics of the Study Area
25
Chapter 5: Case-Study – Methods
Overview
Restrictions to the Scope of Analysis Performed in Steps 1-4
32
33
5
Aerial Photographs
Delineation of the Study Area
Calculation of Total Impervious Area
Time Periods Used
Method Used to Calculate the Rate of Change for Impervious
Surfaces
34
36
37
38
38
Chapter 6: Results, Conclusions, and Recommendations
Overview
Results for Step 1: Change in Land-Cover Categories and Total
Percent Impervious Area Over Time
Change in Land-Cover Categories
Change in Total Impervious Area
Results for Step 2: Timeline for the Adoption and
Implementation of Land-Use Regulations
Results for Step 3: Evaluation of Thurston County’s
Effectiveness at Regulating Impervious Surfaces
Results for Step 4: Summary of Benefits and Limitations
Recommendations
Conclusions
48
49
50
References
52
Appendices
Appendix 1: Thurston County Comprehensive Plan: Chapter 9
– Natural Environment
Appendix 2: The City of Tumwater and Thurston County Joint
Plan: Goal #6 Policy Objectives
Appendix 3: The City of Tumwater and Thurston County Joint
Plan: Goal #8 Policy Objectives
Appendix 4: NLCD Land-Cover Classification System LandCover Class Definitions
40
40
40
44
45
46
56
72
73
74
6
List of Figures
Page #
27
Figure 1
Black Lake 2005 Aerial Photo with 200 foot
Shoreline Area
Figure 2
Zoning District Map for Black Lake’s 200 foot
Shoreland Area
31
Figure 3
Change in Development within Black Lake’s 200
foot Shoreland Area 1937 - 2005
41
Figure 4
Change in Grassland and Forest Areas within Black
Lake’s 200 foot Shoreland Area 1937 - 2005
43
Figure 5
Change in Total Percent Impervious Area for Black
Lake’s 200 foot Shoreland Area 1937 - 2005
44
Figure 6
Regulatory Implementation Timeline
46
Figure 7
Rate of Change in Impervious Surface Coverage
within Black Lake’s 200 foot Shoreland Area
46
7
List of Tables
Table 1
Estimated Percent Impervious Values for LandCover Types
Page #
38
8
Chapter 1: Introduction
Lake ecosystems are particularly fragile since they are closed systems-what enters the soil or water has no means of escape. When development occurs
within lake ecosystems the landscape and relationships present are often
detrimentally altered. The consequences of these alterations involve a multitude
of problems associated with issues of water quality, flooding, the loss of species
within an ecosystem, erosion, landslides, contamination of groundwater, and dead
zones within lakes. Many efforts have been undertaken to address these
challenging problems. The development of new methods of predicting,
preventing, and solving these problems is very important for the creation of
sustainable relationships between people and the ecosystems we inhabit.
A vital component of these efforts is an understanding of how landscapes
have changed over time, and the limits to development. This thesis uses historical
and current landscape information, policy information, and mapping software to
determine the amount of landscape alteration that has taken place over time, as
well as, how effectively land-use regulations have limited development. The
method for this analysis is detailed in a case study of the Black Lake region, in
Washington State.
The four main research questions addressed by this thesis are:
1. Has the amount of impervious surface in the case-study region changed
over time?
2. How are impervious surfaces regulated within the case-study region?
9
3. Have land-use regulations effectively limited increases in impervious
surfaces within the study area?
4. What are the benefits and limitations associated with the use of total
impervious area data as a tool for evaluating regulatory effectiveness in
this part of Thurston County?
Impervious surfaces are those materials that prevent the infiltration of
water into the soil. It is important for the purposes of this project to note that
surfaces actually have different degrees of imperviousness. For instance, concrete
roadways, sidewalks, and patios are 100% impervious, whereas compacted soils,
gravel drives, and manicured lawns are not 100% impervious, but allow for less
water infiltration than natural ground cover such as forests. (Thurston Regional
Planning Council, 2003; Arnold and Gibbons, 1996; May et. al., 1997)
To address these research questions, a case-study was done in Thurston
County using the shoreline around Black Lake within 200 feet of the lake’s edge.
This region was selected after initial research revealed that it is affected by
relevant land-use regulations, and because aerial photosets were available for
eight different years over a 68 year time span. Any effort to expand the study
area would have required the use of a culling method to identify where different
regulations were in effect individually and where they overlapped. After
exploring this alternative, it was abandoned due to limits on continuous coverage
areas for the available photosets and the decision that it would unnecessarily
complicate research efforts.
10
To address the first research question, the total impervious area analysis
method was used to measure the change in impervious surfaces within the casestudy area. Total impervious area is defined as the percentage of land within a
given area that is impervious to water. (May et. al., 1997) This includes the
number of acres covered by rooftops, paved surfaces, and compacted earth. (May
et. al., 1997) This type of analysis was chosen because it is derived from landuse/land-cover data, and is a key indicator of ecological conditions. (May et. al.,
1997) The outputs of this analysis are represented using a percentage. This is a
consequence of the calculation performed that multiplies the quantity of a specific
land-cover type by a coefficient referred to as the ‘percent impervious value’ for
the land-cover type. This calculation is done for each type of land-cover present
within the study area. The results are then added together to determine the total
impervious area for a specific time period. The results of the analyses done
showed a continuous increase in the amount of total impervious area present
within the case-study region over the 68 year time span. Chapter 6 provides a
more detailed analysis of the results.
The second research question required analysis of land-use regulations
that limit impervious surfaces in this part of Thurston County. These regulations
were identified and analyzed for their applicability to the study area. This thesis
evaluates how successful these regulations have been at achieving their goals and
serving the purposes intended. The overall objective is to identify the impervious
surface regulatory structure and background for the study region. The results of
this analysis and a regulatory adoption timeline are provided in Chapter 6. It is
11
important for everyone from policy makers to citizens to monitor and evaluate the
effectiveness of laws and regulations for the sake of the environment and all its
inhabitants, and to recommend amendments or adjustments to these regulations to
improve their efficacy as needed. (R.C. Wissmar, 1993)
The third research question was considered by looking at the total
impervious area in conjunction with policy analysis data. The rate of change for
impervious surfaces was evaluated for different time periods, based on the
regulatory implementation and adoption timeline. The results show that the rate
of change in impervious area varied for different time periods. To be more
specific, the rate of change for impervious surfaces within the study region
continued to rise despite Thurston County’s implementation of the Shoreline
Management Act (SMA) (via adoption of its Shoreline Master Program) in 1976,
and the implementation of the Growth Management Act (via adoption of its GMA
compliant Comprehensive Plan update) in 1995. This topic is discussed in more
detail in Chapter 6.
The fourth research question evaluates how successfully total impervious
area analysis data can be used to measure the effectiveness of impervious surface
regulations both in this case study and in general. The results indicate that
although there were significant restrictions to the depth of analysis that could be
done when evaluating regulatory effectiveness associated with Black Lake’s
shoreland region, in general this method is both thorough and useful. For
instance, future studies could improve results by using different base data sources
or more specialized software. Overall, the benefits of this type of analysis are
12
extensive and allow for a thorough evaluation of how effectively regulations limit
increases in impervious surfaces.
13
Chapter 2 – The Effects of Impervious Surfaces on Ecosystems
There is considerable scientific evidence indicating that an increase in the
amount of impervious surfaces results in ecosystem degradation. Increases in
impervious surfaces come from the transformation of landscapes by a variety of
human activities, commonly referred to as urbanization. Urbanization results in
changes to the amount of impervious surfaces within drainage basins, which alters
hydrological systems, the quantity and toxicity of stormwater runoff, water
quality, habitat availability, natural flow channels for surface water, water
temperature, and vegetative cover. (The Center For Watershed Protection, 2003;
Booth, 1991; Arnold and Gibbons, 1996; Grant et. al., 2000; and Booth, 2000)
All of these changes lead to ecosystem and drainage basin degradation,
particularly for closed systems such as lakes.
As the amount of impervious surfaces increases so does the volume, rate
(peak discharge) and duration of stormwater runoff. (Thurston Regional Planning
Council, 2003) This increase in runoff results in a change to the quantity and
quality of the water that enters the groundwater supply, lakes, streams, rivers, and
wetlands. (Thurston Regional Planning Council, 2003) “Nationwide, the EPA
reports that urban runoff has resulted in, or contributed to, the impairment of: …8
percent of total assessed lake acres.” (U.S. Environmental Protection Agency,
1998) This statistic illustrates why it is important to remember that any pollutant
deposited or derived from an activity on land will likely end up accumulating in
stormwater runoff. (The Center for Watershed Protection, 2003)
14
Closed lake systems are threatened by negative impacts to their water
columns, and sediments from stormwater pollutants, including sediment,
phosphorus, other nutrients, bacteria, metals, hydrocarbons, chlorides, and
trash/debris. (The Center for Watershed Protection, 2003) For example, increases
in phosphorous levels have been directly linked to increases in impervious
surfaces in lake watersheds. (The Center for Watershed Protection, 2003) This is a
concern because phosphorus leads to eutrophication. (The Center for Watershed
Protection, 2003) Eutrophication is the process of increased nutrient input to a
lake over the natural supply. This increased lake fertilization usually results in an
increase in the biological production that occurs in the lake, stimulating excessive
plant growth (algae and nuisance plant weeds). (The Center for Watershed
Protection, 2003) More than 80% of urban lakes show some symptoms of
eutrophication. (The Center for Watershed Protection, 2003) Increases in plant
growth ultimately results in changes to dissolved oxygen levels that degrade
wildlife habitat, recreational opportunities and other beneficial uses. (Hinman,
2005)
Water quality is not the only variable negatively affected by changes in the
quantity and toxicity of the runoff. Urban runoff can also have severe
environmental impacts such as flooding, habitat loss, and erosion. (Booth, 1991;
Grant et. al., 2000; U.S. Environmental Protection Agency, 1997) Other side
effects of changes to runoff are the associated adjustments of water flow channels
and a change in water temperature. (Thurston Regional Planning Council, 2003;
Grant et. al., 2000)
15
As shorelines are converted from natural landscapes to developed
environments, the natural flow channels for surface water are typically altered.
(Thurston Regional Planning Council, 2003; Booth, 2000) Runoff may contain
“water heated on hot pavement and rooftops [which] may cause an elevation in
water temperature in streams, lakes, and wetlands.” (Grant et. al., 2000; Thurston
Regional Planning Council, 2003) The reduction in the amount of vegetative
cover along a lake or stream shoreline may result in a reduction of shade, which
can contribute to the increase in water temperature. (Arnold and Gibbons, 1996;
Thurston Regional Planning Council, 2003) This increase in water temperature is
a concern because it can result in a decrease in dissolved oxygen levels, as well
as, changes to the amount and type of nutrients present in lakes or streams. (Grant
et. al., 2000; Thurston Regional Planning Council, 2003) These types of changes
in nutrient concentrations often create the perfect environment for algae blooms in
lakes, which can also negatively affect coldwater fish and insects. (The Center for
Watershed Protection, 2003; Thurston Regional Planning Council, 2003) The
reproductive capabilities and health of many coldwater fish and insects are very
sensitive to changes in water temperature. (Grant et. al., 2000; Thurston Regional
Planning Council, 2003)
Changes in groundwater levels also pose a significant threat to the health
of a water body. Increases in impervious surfaces lead to decreased infiltration,
which results in reduced groundwater supplies. A decrease in infiltration will
cause the water table to lower and it may also “cause a stream or wetland to dry
out during months when precipitation is low,” since lakes, wetlands, and streams
16
rely on a consistent and continuous ground water supply. (Thurston Regional
Planning Council, 2003; Arnold and Gibbons, 1996)
Over the past 68 years, Thurston County has experienced urbanization and
corresponding increases in impervious surfaces that have led to issues with water
quality and habitat loss. According to the Thurston Regional Planning Council,
“water quality in many of the basins in Thurston County has been degraded due to
the effects of urbanization.” (Thurston Regional Planning Council, 2003) Habitat
has also been degraded as land has been paved over for development purposes. In
Thurston County a variety of regulations have been adopted that address the
issues associated with increases in impervious surfaces and some that specifically
limit the amount of impervious surfaces allowed. The adoption of these
regulations was mandated by state laws such as the Growth Management Act and
the Shoreline Management Act, which will be discussed in later chapters. Other
legislation that apply to the study area will also be discussed in later sections.
17
Chapter 3: Policy Analysis
Overview
There are City, County, and State regulations applicable to the study area
that limit development and impervious surfaces. This thesis focuses on County
regulations, but includes the State regulations that mandate County action, when
applicable. The scope of analysis for this thesis is limited to the identification of
relevant regulations by analysis of their goals, policies, and objectives in order to
establish a regulatory implementation timeline. Data limitations did not allow for
parcel-level analysis.
The primary regulations analyzed were Thurston County’s Shoreline
Management Plan, Thurston County’s Comprehensive Plan, and Thurston
County’s Development Regulations. There are multiple elements within these
three main bodies of regulations, which individually address impervious surfaces
and limit development. These include Thurston County’s: zoning regulations,
Critical Area Ordinance, Joint Plan with the City of Tumwater, and its Drainage
Design and Erosion Control Manual. Some State laws and regulations are also
addressed because they required the County to take action. The two primary ones
mentioned are the Shoreline Management Act and the Growth Management Act.
Other State regulations, such as the Department of Ecology’s Stormwater
Management Manual, are applicable to the study area, but since these regulations
focus primarily on permitting and parcel-level regulations for impervious
surfaces, they are not directly addressed by this thesis.
18
General Background
In 1937, counties and cities received the authority from the State
Legislature. (Washington State History Link, 2007) No requirements regarding
such activities were enacted, however, so any action on the part of counties and
cities was purely optional. (Washington State History Link, 2007) The Shoreline
Management Act (SMA), which regulates development within Washington
State’s shoreline regions, was passed by the Legislature in 1971 and adopted via
public referendum in 1972. (Gates, 2003) The SMA (RCW 90.58) was adopted
around the same time (early 1970’s) as the State Environmental Policy Act
(SEPA), when environmental activism exerted political force here in Washington
State. (Washington State History Link, 2007) During that same time period, there
was also some support for the establishment of a state-wide, land-use planning
act, although draft legislation aimed at this goal was not passed by the
Legislature. (Washington State History Link, 2007) It wasn’t until the early
1990’s that the public once again began to push the legislature to develop and
adopt a state-wide, land-use planning act. In 1990 these efforts were successful.
The Growth Management Act (GMA-RCW 36.70A) was adopted by the
Washington State Legislature in 1990 on the last day of a special legislative
session. (Washington State History Link, 2007; RCW 36.70A)
19
Shoreline Management Act: Background Information
The Shoreline Management Act was adopted in order to “prevent the
inherent harm in an uncoordinated and piecemeal development of the state’s
shorelines.” (Gates, 2003) The SMA balances the desire and need for waterrelated uses, residential development, public access, and the goal of protecting
shoreline environments and water quality. (Gates, 2003) The SMA seeks to
protect shoreline environments and aquatic ecosystems, while allowing for
preferred uses. (RCW 90.58; Gates, 2003) Under the Act preferred uses are
identified that “include single family residences, ports, shoreline recreational uses,
water dependent industrial and commercial developments and other developments
that provide public access opportunities.” (RCW 90.58) The SMA requires strict
mitigation of adverse environmental impacts caused by these preferred uses.
(RCW 90.58) These mitigation standards are intended to preserve the aesthetics
and natural character of the shoreline regions. (RCW 90.58) The details regarding
what uses are allowed and what environmental protections are stated in each
jurisdictions’ Shoreline Master Program. (Gates, 2003)
Shoreline Master Programs
The SMA requires counties and cities to develop and adopt a Shoreline
Master Program (SMP). (Gates, 2003) An SMP is a combination of plans and
regulations detailing what type of development, uses, and activities can occur in
shoreline areas. (Gates, 2003) Since the adoption of the GMA, these programs
must be incorporated into the comprehensive plans of local jurisdictions. Many
local governments either incorporate them via reference or add them as another
20
element of their comprehensive plans. (Municipal Research and Services Center
of Washington, 2007) An SMP is “based on state laws and rules but tailored to the
specific geographic, economic and environmental needs of the community.”
(RCW 90.58; Gates, 2003) The Washington State Department of Ecology has
approval authority over all SMP amendments, as a safeguard to ensure that the
standards of the SMA are met within all adopted SMPs. (RCW 90.58)
Requirements for the Shoreline Management Act’s Purview to be Applied:
The SMA applies to all marine waters, streams with an average annual
flow greater than 20 cubic feet per second, lakes with surface areas 20 acres or
larger in size, upland areas called “shorelands” that extend 200 feet landward
from the edge of these waters, and the following areas when they are associated
with one of the above: biological wetlands and river deltas; and some or all of the
100-year floodplain including all wetlands within the 100-year floodplain. (RCW
90.58; Gates, 2003) The SMA also identifies shorelines of statewide significance:
Pacific Coast, Hood Canal, certain Puget Sound shorelines, all waters of Puget
Sound and the Strait of Juan de Fuca, lakes or reservoirs with surface areas of
more than 1,000 acres, larger rivers (1,000 cubic feet per second or greater for
rivers in Western Washington, 200 cubic feet per second and greater east of the
Cascade crest), and wetlands associated with the areas listed above. (RCW 90.58;
Gates, 2003) The SMA states that “the interests of all the people shall be
paramount in the management of shorelines of statewide significance.” (RCW
90.58; Gates, 2003) The Shoreline Management Act applies to more than 20,000
21
miles of shorelines: 2,300 miles of lake shores, 16,000 miles of streams, and
2,400 miles of marine shoreline. (Gates, 2003)
Thurston County’s Shoreline Master Program – Goals, Policies, and
Objectives Relating to Impervious Surfaces
Thurston County’s Shoreline Master Program (SMP) was originally
adopted in 1976 and has since been updated twice, most recently in 1990. One of
the stated policies of the County’s SMP is:
“Uses shall be preferred which are consistent with control
of pollution and prevention of damage to the natural
environment or are unique to or dependent upon use of the
State’s shoreline.” (Thurston County Shoreline Master
Program, 1976, Section Two (III.))
The SMP’s policies indicate that the allowed land-uses within shoreland areas
must be designed and orchestrated in a way that causes only minimal damage to
the ecosystem of the shoreline area, to the extent feasible. (Thurston County
Shoreline Master Program, 1976, Section Two (III.)) The SMP gives priority to
the protection of the natural character of the shoreline and the shoreline’s ecology.
(Thurston County Shoreline Master Program, 1976, Section Two (IV.)) Thurston
County goes beyond listing the protection of water quality and shoreline
ecosystems as a priority. It specifically requires all development to avoid
adversely affecting aquatic habitats and water quality. (Thurston County
Shoreline Master Program, 1976, Section Two (V.))
More specific restrictions are found within the specific standards for each
of the Shoreline Environment designation categories. A shoreline environment
designation area is a category of shoreline that is applied to regions based on the
22
amount of man-made development present and the uniqueness of the area. There
are five categories of shorelines specified within Thurston County’s Shoreline
Master Program, and they are: Natural, Conservancy, Rural, Suburban, and Urban
Environments. (Thurston County Shoreline Master Program, 1976, Section Two
(VII.)) Each of these five categories has their own specific goals and purposes.
The restrictions on impervious surface coverage, and development in general, is
different for each category. The Natural category is the most restrictive in that it
seeks to limit development and public access at a level that is compatible with
maintaining the area’s unique undeveloped environment. (Thurston County
Shoreline Master Program, 1976, Section Two (VII.)) Each subsequent category
is less restrictive in terms of the amount of development and impervious surface
coverage allowed. These unique environmental designation areas are applied to
specific regions of Thurston County, and supercede other land-use regulations for
those areas that are less restrictive. (Thurston County Shoreline Master Program,
1976). The application of the standards for these categories on the shorelines of
Thurston County are aimed at providing protection for aquatic and semi-aquatic
ecosystems, while still allowing human uses within shoreland areas.
The Growth Management Act: Background Information
The GMA lays out a state-wide, land-use planning system that seeks to
guide development, while protecting environmental, economic, and private
property interests, through the adoption of plans, policies, and regulations at the
local-government level. Since its adoption in 1990, the GMA has been amended
23
multiple times, first in 1991 to create enforcement entities called the Growth
Management Hearings Boards, which deal with “allegations of non-compliance
with the GMA.” (RCW 36.70A) Other amendments have been added in
subsequent years to clarify and/or expand the Act’s provisions. (RCW 36.70A)
“The GMA requires state and local governments to manage Washington’s
growth by identifying and protecting critical areas and natural resource lands,
designating urban growth areas, preparing comprehensive plans and
implementing them through capital investments and development
regulations.” (RCW 36.70A)
The GMA ensures that counties and cities undertake comprehensive land-use
planning efforts. Local governments are required to adopt comprehensive plan
policies and development regulations to implement those policies. (RCW 36.70A)
The Growth Management Act’s Planning Goals
The GMA specifically identifies and states 13 planning goals to guide
jurisdictions in the preparation of their comprehensive plans and development
regulations. These are found in the following section of the GMA: RCW
36.70A.020 Planning Goals. (Washington State History Link, 2007) No priority is
given to any one planning goal. (RCW 36.70A) This demonstrates the
legislature’s intent of requiring jurisdictions to balance the goals, in an attempt to
give them equal consideration when developing plans and regulations. Goal
number ten addresses the environment: “Protect the environment and enhance the
state’s high quality of life, including air and water quality, and the availability of
water.” (RCW 36.70A)
24
The Growth Management Act: How it Applies to The Study Area – Overview
The Growth Management Act pertains directly to the study area, as it is
the mandate that requires Thurston County to draft its Comprehensive Plan and
Development Regulations. Zoning districts are identified in the Thurston County
Comprehensive Plan, and regulations stipulating what activities are allowed
within each zoning district are outlined in the corresponding development code.
The Thurston County Critical Area Ordinance and Shoreline Master Plan are
housed in the County development regulations. The drainage design and erosion
control manual is also a part of the County code. The City of Tumwater and
Thurston County Joint Plan applies to the Tumwater urban growth area, which
covers the eastern portion of the study region. The joint plan is incorporated into
the County’s Comprehensive Plan.
Thurston County Comprehensive Plan – Goals, Policies, and Objectives
Relating to Impervious Surfaces
Chapter 9 of the Thurston County Comprehensive Plan addresses the
natural environment. The language found throughout this chapter acknowledges
the importance of protecting the County’s natural environment and the challenge
of doing so, while balancing the need to sustain human uses. As stated in Chapter
9, county-wide planning policies 9.1 through 9.8 call for jurisdictions in the
county to protect ground and surface water from degradation, and to plan for
sustainable growth so that human uses can be accommodated without
jeopardizing the County’s livability and environmental quality. (Thurston County
25
Comprehensive Plan, 1995a, Chapter 9) Appendix 1 in this thesis lists the specific
policies stated in chapter 9 of the County’s Comprehensive Plan that address the
protection of the natural environment from the effects of increased impervious
surfaces. These effects include the degradation of groundwater and surface-water
supplies. These policies specifically call for limitations on development in order
to protect and improve the water quality and biological health of lakes and other
water bodies or aquatic systems throughout Thurston County. (Thurston County
Comprehensive Plan, 1995a, Chapter 9(III.)(C)) Limitations on the amount of
allowed development are also recommended to protect groundwater quality and
quantity. (Thurston County Comprehensive Plan, 1995a, Chapter 9(III.)(B))
Limitations to impervious surfaces are being construed as limitations to
development; however, it is important to note that limitations to impervious
surfaces are also specifically called for in the County’s policies and goals. In
summary, Thurston County’s Comprehensive Plan outlines clear goals,
objectives, and policies that seek to prevent ecosystem degradation by evaluating
and limiting the amount of impervious surfaces.
Urban Growth Areas and Joint Plans
An Urban Growth Area (UGA) is an area outside a city boundary that is
designated for future urban growth. (The City of Tumwater and Thurston County
Joint Plan, 1995b, Chapter 1) Within the urban growth area, the County enforces
the City’s zoning regulations and environmental standards. The GMA requires
counties and the cities that they encompass to “establish a 20-year growth
boundary for each urban area.” (The City of Tumwater and Thurston County Joint
26
Plan, 1995b, Chapter 1) These UGAs are areas where the counties and cities plan
for future development at urban densities. (The City of Tumwater and Thurston
County Joint Plan, 1995b, Chapter 1)
A joint plan is essentially a comprehensive plan for the unincorporated
portion of a city’s urban growth area, developed through a cooperative effort
between a city and the county. (The City of Tumwater and Thurston County Joint
Plan, 1995b, Chapter 1) The joint plan is then “adopted by each jurisdiction as a
comprehensive plan amendment.” (The City of Tumwater and Thurston County
Joint Plan, 1995b, Chapter 1) The Joint Plan is developed to establish guidelines
for the transition from rural to urban development densities that are intended to
occur within a UGA. (The City of Tumwater and Thurston County Joint Plan,
1995b) As both cities and counties are subject to the GMA, the Act’s provisions
and planning goals serve as the framework for the creation of joint plans, just as
they do for the creation of comprehensive plans and development regulations.
City of Tumwater and Thurston County Joint Plan – Goals, Policies, and
Objectives Relating to Impervious Surfaces
Goal number 6 of the City of Tumwater and Thurston County Joint Plan is
to reduce the impacts from flooding, encourage efficient stormwater management,
and ensure that the groundwater of Tumwater is protected and preserved. (The
City of Tumwater and Thurston County Joint Plan, 1995b, Chapter 3) The policy
objectives listed for goal number 6 seek to ensure that future land use and
development conform to the County’s and City’s standards for groundwater
27
(wellhead and aquifer) and surface-water protection. (The City of Tumwater and
Thurston County Joint Plan, 1995b, Chapter 3) These policy objectives are listed
in their entirety in Appendix 2.
Goal number 8 also addresses the need for protecting the County’s water
resources, and environmentally sensitive areas. The stated goal is: “[To] ensure
that physical limitations of the land are observed during the development
process.” (The City of Tumwater and Thurston County Joint Plan, 1995b, Chapter
3) This goal addresses the actual development or construction processes, yet it
also broadly calls for the jurisdictions to “prohibit or set conditions on
development based on anticipated adverse environmental impact[s].” (The City of
Tumwater and Thurston County Joint Plan, 1995b, Chapter 3) Additional details
regarding goal number 8’s policy objectives are found in Appendix 3. The
following is a summary of the land uses and zoning districts found within the
study area.
Development Regulations
Jurisdictions draft development code language, which includes zoning,
subdivision, landscaping, critical areas, and other development regulations, in
order to implement comprehensive plan policies. (Municipal Research and
Services Center of Washington, 2007) Consistency is therefore required between
comprehensive plans and development regulations. (Municipal Research and
Services Center of Washington, 2007)
28
Zoning Regulations:
Zoning regulations are the component of development regulations that control the
density of development throughout the county or city. Zoning districts are blocks
of land with identified boundaries where specified activities and development
densities are allowed. Zoning regulations have associated zoning maps that show
a county with blocks of land shaded in different colors to signify their zoning.
Zoning densities are typically defined in terms of how many dwelling units are
allowed on a specified number of acres. For example, a zoning density of 1:5
means that one dwelling unit (house) is allowed per five-acre parcel. Zoning
regulations also set up specific zones for different types of land-uses.
Commercial, Industrial, Long-Term Agriculture, Long-Term Forestry, and Rural
Residential are typical zoning districts found in most counties. Each zoning
district has regulations pertaining to allowed uses, environmental protection, and
development density—to name a few. Simply put, zoning is a tool that
jurisdictions use to say where and in what quantities or types development can
occur.
Critical Area Ordinances:
Under the GMA, a required component of development regulations for
local governments are those pertaining to environmentally critical areas. (RCW
36.70A) This body of regulations is commonly referred to as a Critical Areas
Ordinance (CAO). The definition provided for Critical Areas in the GMA is as
follows: “ ‘Critical areas’ include the following areas and ecosystems: (a)
wetlands; (b) areas with a critical recharging effect on aquifers used for potable
29
water; (c) fish and wildlife habitat conservation areas; (d) frequently flooded
areas; and (e) geologically hazardous areas.” (RCW 36.70A) The CAO
establishes regulations to protect these environmentally critical areas and limit the
amount and type of development that can occur on or around such areas.
Thurston County’s Critical Area Ordinance – Goals, Policies, and Objectives
Relating to Impervious Surfaces
Thurston County’s Critical Area Ordinance states as one of its main
purposes the goal of protecting unique, fragile, and vulnerable elements of the
environment. (Thurston County Development Code, 1997, Chapter 17.15) Each
type of critical area has a separate section of code that distinguishes goals and
policies for its protection. For example, the main goals for the Critical Aquifer
Recharge Area section are the prevention of degradation to groundwater sources
and the maintenance of groundwater recharge. (Thurston County Development
Code, 1997, Chapter 17.15) The section on geologic hazards is primarily aimed
at protecting people from the hazards of landslides, erosion, and seismic and
volcanic activities. In addition, the protection of stream quality, fish and marine
shellfish is also set forth as a primary purpose. (Thurston County Development
Code, 1997, Chapter 17.15) The section on important habitat and species deals
with the protection and preservation of wildlife habitat areas, especially habitat
areas for wildlife native to Thurston County. (Thurston County Development
Code, 1997, Chapter 17.15) Finally, the floodplains, streams, and wetlands
portion lists numerous policies relevant to impervious surfaces that Thurston
County is mandated to accomplish. The policies are: a) to preserve natural flood
30
control, stormwater storage and drainage or stream flow patterns; b) to control
siltation, protect nutrient reserves and maintain stream flows and stream quality
for fish and marine shellfish; c) to prevent turbidity and pollution of wetlands,
streams and fish or shellfish bearing waters and to maintain the associated wildlife
habitat; and d) to minimize the loss of wetlands and to increase the quality and
function of wetlands within Thurston County. (Thurston County Development
Code, 1997, Chapter 17.15)
All of the purposes and policies noted for each section of the Critical
Areas Ordinance relate to protection of water quality, habitat, and groundwater or
surface-water supplies. The exact standards or limitations for impervious surfaces
for each section include restrictions on lot coverage, density and allowed
development or uses within critical areas. These are not detailed further in this
section. Only the effectiveness of the broad goals, policies, and purposes are
being evaluated as a part of this thesis.
Thurston County’s Drainage Design and Erosion Control Manual – Goals,
Policies, and Objectives Relating to Impervious Surfaces
Thurston County has its own Drainage Design and Erosion Control
Manual, which was adopted in 1994. Thurston County and its cities are currently
working collaboratively to update the 1994 manual. The general intent of the
manual is to:
“Define policies, minimum requirements, minimum standards, and
procedures for the design, construction, and maintenance of drainage
facilities and for the control of erosion on construction sites. Where
structures are necessary to treat runoff and to control flow…[the] manual
31
will promote the construction of multiple use drainage facilities.”
(Thurston County Drainage Design and Erosion Control Manual, 1994)
The manual “also provides standard procedures for estimating flow from and
establishes allowable runoff criteria for developed property.” (Thurston County
Drainage Design and Erosion Control Manual, 1994) Guidelines for construction
of stormwater facilities (conveyance, detention, retention, and infiltration), which
must be followed by jurisdictions located in Thurston County, are also included in
the Drainage Design and Erosion Control Manual. This manual limits the amount
of allowed impervious surface at the parcel level. It has specific standards for
individual parcels relating to building footprints and the amount of impervious
surfaces allowed during and after the construction phase. It also has
specifications for stormwater infiltration, retention, and treatment for specific
parcels. These specific standards were not analyzed as a part of this thesis.
32
Chapter 4: Case-Study - Overview
Characteristics of the Study Area
Black Lake (Figure 1) is a cold water lake located in northwestern
Thurston County. It is 570 acres and approximately 2.4 miles long, with a mean
depth of 19 feet and a volume of 11,000 acre/feet. (Thurston County Department
of Environmental Health, 2005) The lake drains through a ditch on the north end
into Percival Creek. (Thurston County Department of Environmental Health,
2005) Historically, the lake drained to the south through the Black River, but this
route is now blocked by beaver dams and vegetation. (Thurston County
Department of Environmental Health, 2005) Black Lake’s shoreland area is also
characterized by the presence of some small wetland areas, with limited areas of
hydric soils and small patches of high groundwater hazard areas. For the most
part, these areas are found on the north and south tips of Black Lake, although
there are also wetlands located on the lake’s east side, where two tributaries
originate. (Thurston County Department of Environmental Health, 2005) On the
lake’s west side there is one larger tributary and several intermittent streams that
flow into the lake. (Thurston County Department of Environmental Health, 2005)
The soils in the shoreland area are primarily variations of loam including silt
loam, very gravelly loam, clay loam, and sandy loam. (Thurston County Geodata
Center, 2007)
33
Figure 1. Black Lake 2005 Aerial Photo with 200 foot Shoreline Area
Delineated
Aerial photos for this image are provided by the Thurston County Geodata Center - www.geodata.org
34
During 2005, the water quality of Black Lake was assessed by Thurston
County staff. On a rating scale of “Excellent, Good, Fair, and Poor,” Black Lake
was rated as having “Fair” general water quality. (Thurston County Department of
Environmental Health, 2005) Major issues with the water quality in Black Lake
include: a) the occurrence of blue-green algae blooms, which can prevent
recreational use of the lake; b) beaver activities in outlet ditches on the north
section of the lake, which can lead to rises in water levels and the flooding of
yards and docks; and c) the occurrence of swimmer’s itch on a regular basis
during the summer, which is a health concern for recreational users. (Thurston
County Department of Environmental Health, 2005) Overall, the 2005 assessment
found the lake to have moderate to high nutrient concentrations that led to bluegreen algae growth in late summer and fall.
The most pressing of these issues is the occurrence of algae blooms. There
are a number of algae types common to Black Lake including: diatoms, and green
and blue-green algae. The blue-green algae Aphanizomenon sp. or Anabaena sp.
are considered to be the dominant algae in Black Lake. (Thurston County
Department of Environmental Health, 2005) The dominance of blue-green algae
is generally considered a sign of nutrient-rich conditions and poor water quality.
(Thurston County Department of Environmental Health, 2005) Blue-green algae
growth has been responsible for algae blooms in Black Lake on multiple
occasions. In September 2000, much of the western shore of Black Lake was
covered by a spectacular blue-green algae bloom, which at the point of algae dieoff, resembled a turquoise-blue paint spill. (Thurston County Department of
35
Environmental Health, 2005) Another smaller bloom occurred in August of 2004
and resulted in the closure of the County’s swimming area at Kenneydell Park.
(Thurston County Department of Environmental Health, 2005) Recreational use is
frequent for Black Lake. There are numerous private access points to Black Lake,
including private residences, one church camp, two private resorts, and three
small private community accesses. (Thurston County Department of
Environmental Health, 2005) There are also two public accesses: the Washington
Department of Fish and Wildlife public boat launch and Kenneydell County Park.
(Thurston County Department of Environmental Health, 2005)
The south, west and north portions of Black Lake’s shorelands are within
unincorporated Thurston County. The eastern portion falls within the City of
Tumwater’s Urban Growth Area, thus urban growth will move into this part of the
basin as the city expands. As this portion of the shoreland area is regulated by a
Joint Plan crafted collaboratively by Thurston County and the City of Tumwater;
this section of shoreland is subject to specialized regulations that reflect the
anticipated transition within the UGA from rural to urban development.
A description of the primary land-uses surrounding Black Lake is
provided by Thurston County Waste and Water Management Staff: “A large
percentage of the lake shore is moderate density residential. There are two large
mobile home parks on the east shoreline and two RV commercial resorts on the
west side of the lake.” (Thurston County Department of Environmental Health,
2005) The south end of the lake is primarily undeveloped land due largely to its
proximity to the Black River wetland system.
36
There are multiple zoning designations within the Black Lake shoreland
area. A zoning designation determines the density (number of dwelling units,
etc…) allowed in a particular area, as well as the types of uses and the amount of
lot coverage allowed, and is represented by an abbreviation of the full
designation’s name, and a ratio representing the number of dwelling units allowed
per a certain number of acres. This density ratio can be represented via one of the
following notations: a) 1/5, b) 1:5, or c) 1du per 5 ac. The zoning designations for
the shoreland areas surrounding Black Lake are as follows: Rural Residential
Resource (RRR) 1/5, Rural Residential (RR) 1/2, Single Family Low-density
(SFL) 4/7, Green Belt (GB), Tumwater Urban Growth Area Open Space (OS),
Multi-Family Medium Density Residential (MFM) 9/15, Rural Residential (RR)
2/1, Parks, Trails, and Preserves (PP), and Neighborhood Convenience (NC).
Figure 2 gives the distribution of these zoning districts, and the embedded table
provides information on the number of acres that fall within each zoning district
within the study area’s boundaries.
Each of these zoning designations has specific standards restricting lot
coverage by impervious surfaces, and allowed development densities. The
allowed impervious surface or lot coverage standards range from 60% to 85% of
the individual lot for the zoning districts listed above with the exception of the PP,
GB, and OS zoning districts. This thesis did not perform parcel-level analysis so
an evaluation of how consistently and effectively these standards have been
applied is not possible; however, the cumulative effects can be measured by
37
looking at the rate of change in impervious surface before and after the
implementation of these districts.
38
Figure 2. Zoning District Map for Black Lake’s 200 foot Shoreland Area
Created by: Amy Calahan, GIS Analyst – Thurston County Geodata Center
39
Chapter 5: Case-Study – Methods
Overview
The data used for this case-study were gathered from aerial photographs of
the Black Lake region spanning the time period from 1937 to 2005. These
photographs were scanned, geo-rectified, and when necessary, mosaics were
created. The boundary for Black Lake was then digitized and a 200 foot buffer
established to create the study area. Finally, land-cover types were delineated and
digitized.
After completing the aerial photography processing and land-cover
classification, the percent of impervious surface for each land-cover type was
calculated. Those data were then used to calculate the total impervious area for
each year of photo coverage. Four main analytical steps were then taken:
1) The change in total impervious area was calculated to determine how
the study area has changed over the 68 year time span.
2) Regulations that limit impervious surfaces within the study area were
identified, and an adoption and implementation timeline was created to
determine when regulatory changes took effect.
3) The regulatory adoption and implementation timeline created in step 2
was used as a guide to divide the total impervious area data into
specific timeframes. The overall change in the percent of total
impervious surfaces and the corresponding rate of change were then
calculated within these timeframes, in order to evaluate how
40
effectively regulations have limited increases in impervious surfaces
within the study area.
4) The benefits and limitations associated with using total impervious
area data as a tool were identified to evaluate how effectively
implementation of regulations limit impervious surfaces.
Restrictions to the Scope of Analysis Performed in Steps 1-4
Due to the nature of the data used for this particular case-study, there were
some restrictions on the scope of this evaluation. The resolution of the photo sets
available was not precise enough to allow for parcel-level analysis of the study
region. The lack of parcel data for all the years that aerial photos were available
also prevented parcel-level analysis within the study area. Therefore, an
evaluation of changes in impervious surfaces was done for the whole study area,
and the goals, intents, and general policy guidelines for the regulations were
analyzed instead of the specific parcel-level standards.
It is also important to note that analysis of the effectiveness of the
regulations at achieving their intended goals was done using only the change in
impervious surface variable. Although other variables (economic, social, and
political) may influence the effectiveness of regulations, this analysis focuses on
whether there is a quantifiable relationship between the implementation of
regulations and changes in the amount of impervious area present within the study
region.
41
Aerial Photographs
Aerial photos from 1937 and 1944 were used to calculate a baseline for
impervious surface prior to the implementation of the Shoreline Management Act
(SMA). Photo sets from 1977, 1980, 1992, 1996, 2000, and 2005 were used to
calculate the amount of total impervious surface present after the adoption of the
SMA. The rate of change in total impervious area was calculated using these
photos for the pre-SMA and post-SMA time periods.
Aerial photos from 1937, 1944, 1977, 1980 and 1992 were used to
calculate a baseline for impervious surfaces prior to the implementation of the
Growth Management Act (GMA). Photo sets from 1996, 2000, and 2005 were
used to calculate the amount of impervious surface present after the adoption of
the GMA. The rate of change in total impervious area was calculated for these
time periods using the same photo sets.
The aerial photos were processed using geographic information systems
software from ESRI. Specifically the software used was ESRI’s 9.1 ArcGIS suite
of products. The land-cover data files were created using this same ESRI
software, and the total impervious area calculations were done by exporting
attribute table data from the ArcGIS software to Microsoft’s Excel program.
1937
These black and white aerial photos were obtained from Thurston
County’s Roads and Right-of-way Department. The scale of the photos is
1:12,000. These photos were saved as image files, and imported into ArcGIS
software. Then the images were geo-rectified and placed into a mosaic.
42
1944
These black and white aerials were taken by the Army Corp of Engineers
at a scale of 1:20,000, as part of a wartime reconnaissance effort. They are housed
at the Evergreen State College Library–maps section. These photos were scanned,
geo-rectified, and clipped to achieve proper alignment.
1977
The aerial photos taken in 1977 are referred to as the Thurston Block and
were obtained from the University of Washington Library’s map and photo
collection. They are black and white, taken at a scale of 1:20,000, and were
originally from the Washington State Department of Transportation. These
photos were scanned, geo-rectified, clipped, and tiled.
1980
The 1980 aerial photos are referred to as Thurston Met, and are in color
and have a scale of 1 to 24,000. They were originally taken by the Washington
State Department of Transportation, but are now housed in the University of
Washington Library’s map and photo collection. After scanning these images,
they were geo-rectified, clipped and tiled to remove blank data spaces
automatically added during the geo-rectification process.
43
1992, 1996, 2000, and 2005
The aerial photos from 1992, 1996, 2000, and 2005 came from Thurston
County’s Geodata Department. They were already geo-rectified and in some
cases tiled. The scale of the photos is 1: 20,000.
Delineation of The Study Area
The study area was defined for each set of aerial photos by loading the
datasets into ArcMap and using ArcToolbox to create a 200 foot buffer around the
digitized boundaries of Black Lake. A polygon defining the boundaries for Black
Lake was created for each of the photo sets, since the boundaries change over
time. Likewise, the 200 foot buffer was defined separately for each data set.
Digitization/Delineation of Land-cover Types
The selection of a land-cover classification system is required in order to
perform a total impervious area analysis. The National Land-cover Type project’s
classification system (NLCD) was selected due to its use in other research that is
similar in nature, in an effort to ensure that the data created could be used for
other inquiries. Land-cover coefficients were then chosen to reflect the area’s
ecosystem characteristics. These selections incorporate the main assumptions
made when identifying methods for analyzing the change in impervious surfaces
within the study region.
Land-cover types were delineated using the NLCD guidelines for the landcover classifications (Appendix 4). The land-cover categories were then digitized
44
using the following steps: 1) import into ArcMap; 2) create a geodatabase to
house feature class datasets for that photo set using ArcCatalog; and 3) use onscreen digitization to create feature classes for each land-cover category. These
steps were repeated for each of the photo sets listed above.
Calculation of Total Impervious Area
The percent of total impervious area within the Black Lake 200 foot
shoreland area was calculated for the years 1937, 1944, 1977, 1980, 1992, 1996,
2000, and 2005 using the following methods. The 200 foot Black Lake shoreland
study area was determined for each year analyzed. Within the established study
area land-cover types were delineated and digitized into polygons. The
percentage of impervious surface for each polygon of land-cover type was then
estimated. The coefficients in the calculation of percentage of impervious surface
for each land-cover type are presented below in Table 1, and are based on values
determined by Karr 1998 and Booth et al. 2001. From these data, an estimate of
the total impervious area within the shoreland area surrounding Black Lake was
calculated.
45
Table 1. Estimated percent impervious values for land-cover types
Land-cover Type
Percent
Impervious
Source
Agriculture
0
Karr (1998)
Forest
3
Grasslands: grass, pasture, bare earth,
recent clear cuts, scrub/shrub,
herbaceous
5
Low Intensity Residential
30
Karr (1998)
High Intensity Residential
44
Karr (1998)
Commercial/Industrial/Transportation
80
Karr (1998)
Booth et al.
(2001)
Booth et al.
(2001) & Karr
(1998)
Time Periods Used
The following time frames were used, based on years that regulations were
actually implemented in the study area: 1) pre-SMP: using the 1937 and 1944
datasets; 2) post-SMP and pre-GMA (the 1995 date is used to reflect the actual
implementation within the study area): using the 1977, 1980, and 1992 datasets;
and 3) post-SMP and post-GMA: using the 1996, 2000, and 2005 datasets.
Method Used to Calculate the Rate of Change for Impervious Surfaces
The rate of change for total impervious area was determined for the
timeframes discussed above, which correspond with the adoption of impervious
surface regulations. The rate of change in total impervious area was calculated
using the following equation: (X1-X2)/Y Where, X1 and X2 represent total
46
impervious acreages for two different data sets, and Y equals the number of years
between the two data sets.
47
Chapter 6: Results, Conclusions, and Recommendations
Overview
The results of the total impervious area analysis and policy analysis for the
case study area are detailed below. Information regarding specific land-cover
types provides a look at how the landscape has changed over time, and the rate of
change data illustrates how fast the alteration occurred. The research done for this
thesis indicates that total impervious area analysis data can be used to evaluate
how effective regulations have been at limiting increases in impervious surfaces
within the study area. This is primarily done by looking at the rate of change data
in combination with the regulatory implementation timeline.
Results for Step 1: Change in Land-Cover Categories and Total Impervious
Area Over Time
Change in Land-Cover Categories
Changes in individual land-cover types were assessed over the time span
of available data. Within Black Lake’s 200 foot shoreland area, the following
land-cover types were identified: forest, grassland, low intensity residential, high
intensity residential, and commercial/industrial/transportation. No agricultural
lands were identified. This type of specific land-cover type change information is
necessary to perform the total impervious area analysis for this thesis. These data
are also worth examining for their potential to answer a variety of specific landuse questions regarding the study area.
48
Figure 3. Change in Development within Black Lake’s 200 foot Shoreland
Area 1937 - 2005
Change in Developed Areas 1937 - 2005
50
45
40
Low Intensity
Residential
35
Acres
30
High Intensity
Residential
25
20
Commercial,
Industrial, and
Transportation
15
10
5
0
1920
1940
1960
1980
2000
2020
Year
As shown in Figure 3, high intensity residential, and
commercial/industrial/transportation land-cover types continually increased over
the last 68 years. Low intensity residential development increased up until 2000.
Between 2000 and 2005 it decreased by 5 acres. The cause for this decrease is
unknown; however, my assumption is that some low intensity residential acreage
was converted to high intensity residential or commercial/industrial/transportation
acreage during that time period. High intensity residential development was
nonexistant in 1937 and 1944. It wasn’t until 1977 that approximately 8 acres of
this type of development was recorded. In comparison,
commercial/industrial/transportation land-cover areas had the smallest increase,
only 6 acres between 1937 and 2005. It is interesting to note that 3 acres of this
49
type of land-cover was present in 1937, which is more than the combined total for
the two land-cover types associated with development. One possible explanation
is that clear-cutting was occurring extensively within the study area in 1937, and
the predominant type of development was the infrastructure supporting logging
activities.
The logging or clear-cutting that occurred prior to 1937 is likely also
responsible for the small amount of forested land within the study area in 1937,
only 55 acres. Figure 4 shows that the amount of forested land increased up to 84
acres from 1937 to 1977, likely due to re-growth. Then from 1977 to 2005 the
number of forested acres steadily declined to 57 acres in 2005, ironically quite
close to the amount found in 1937. By 2005, the forested acres had been largely
replaced by development, rather than clear-cutting activities. Therefore, the
possibility of re-growth or a repeat of the increase in forested land like the one
experienced between 1937 and 1977 is highly unlikely. In general, forestlands
fluctuated over the 68 year time span covered by this thesis, as did grasslands.
50
Figure 4. Change in Grassland and Forest Areas within Black Lake’s 200
foot Shoreland Area 1937 - 2005
Changes in Grassland and Forest Areas 1937 - 2005
100
90
80
70
Acres
60
Forest
50
Grassland
40
30
20
10
0
1930
1940
1950
1960
1970
Year
1980
1990
2000
2010
The number of acres covered by grasslands decreased from 94 acres in
1937 to approximately 27 acres in 2005. Yet from 1980 to 2005 grasslands
increased from a low of 23 acres in 1980 to 29 acres in 1992 and then back down
to 27 acres in 2005. This change over 25 years may be attributable to forestlands
being cleared, which created more grasslands. This is uncertain speculation,
however, and needs verification from a more in-depth investigation, which was
outside the scope of this thesis. Overall, grasslands experienced the most
significant change with close to 70 acres being converted to other land-cover
types over this study’s time span.
51
Change in Total Impervious Area
The quantity of each land-cover type was determined and used to calculate
the total impervious area present for each aerial photo set. The changes in the
amount of total impervious area within the study region are given in Figure 5.
Figure 5. Change in Total Percent Impervious Area for Black Lake’s 200
foot Shoreland Area 1937 - 2005
Total Percent Impervious Area
25%
Percent Impervious
20%
15%
10%
5%
0%
1920
1940
1960
1980
2000
2020
Years
From 1937 to 2005, the total impervious area found within the study area
increased from 6% to 20%. The amount of impervious area steadily increased
between 1944 and 1977, from 6.5% to 12.5% over that 33 year time period.
However the greatest increase over a short time span occurred from 1977 to 1980.
During this time period the total impervious area increased from 12% to 15% for
a 3% increase in just three years. In general the 14% increase in total impervious
52
area is a concern for the study area, as is the total of 20% impervious area present
in 2005.
The threshold for the amount of impervious surface coverage that leads to
ecosystem degradation in a drainage basin is thought to be 10%. (Booth and
Jackson, 1997; Alberti et. al., 2006) Although the study area is not an entire
drainage basin, the threshold is still a relevant measure for concern, as Black Lake
is a closed system and the shoreland area is a small region directly connected to
the water’s edge. Based on this assumption, the 20% total impervious area found
within the study area in 2005 implies that ecosystem degradation is occurring due
to the effects of impervious surface coverage. The data also indicate that the
amount of total impervious area is continually increasing and therefore, any
existing ecosystem degradation is likely to continue.
Results for Step 2: Timeline for the Adoption and Implementation of LandUse Regulations
The policy analysis performed for this thesis yielded two state laws that
mandate the majority of Thurston County’s land-use regulation policies pertaining
to impervious surface limitations. These two are the Shoreline Management Act
and the Growth Management, which were described in detail in Chapter 3.
Thurston County adopted a Shoreline Master Program to comply with the SMA
and a Comprehensive Plan to comply with the GMA. The implementation dates
for these two sets of regulations were used for the regulatory evaluation process
undertaken in Step 3. Figure 6 provides the complete timeline and specific
adoption dates.
53
Figure 6. Regulatory Implementation Timeline
1972
1976
Adoption of
the Shoreline
Management
Act
1990
Adoption of the
Thurston County
Shoreline Master
Program
Adoption of
the Growth
Management
Act
1995
Adoption of the
Thurston County
GMA compliant
Comprehensive Plan
Results for Step 3: Evaluation of Thurston County’s Effectiveness at
Regulating Impervious Surfaces
Figure 7 shows how the rate of change for impervious surfaces has varied
over the 68 year time span were categorized by the dates for adoption and
implementation of the applicable regulations analyzed in this thesis.
Figure 7. Rate of Change in Impervious Surface Coverage within Black
Lake’s 200 foot Shoreland Area
Impervious Surface Coverage Rate of Change (ac/yr)
0.45
0.4
Acres per Year
0.35
0.3
0.25
0.2
0.15
0.1
0.05
0
1937 - 1944
1977 - 1992
1996 - 2005
Time Periods (years)
54
The time periods represented in Figure 7 were established to show the rate
of increase in impervious area before and after the implementation of specific
regulations. Analyzing the rate of change in the percent of total impervious
surface in combination with the dates that key regulations were implemented,
provides a way to evaluate regulatory effectiveness. When looking at Figure 7 it
is important to remember that although the Shoreline Management Act was
adopted in 1972, Thurston County did not adopt its first Shoreline Master
Program until 1976. Similarly, although the Growth Management Act was
adopted in 1990, Thurston County did not update its comprehensive plan to come
into compliance with the GMA until 1995.
The results of the analysis performed in this thesis indicate that neither the
implementation of the Shoreline Management Act or the Growth Management
Act halted the rate of increase in impervious area within the study region. The rate
of change from 1937 – 1944 was 0.06 acres/year and this increased for the years
1977 – 1992 to 0.36 acres/year. The rate increased further for the years 1996 –
2005 to 0.42 acres per year. Therefore, the implementation of these regulations
did not slow the rate at which landscapes are being covered by impervious
surfaces. The rate of increase in impervious surfaces is still increasing after the
implementation of both of these regulations. Therefore, it is clear that additional
regulations or alternative efforts are needed to counter this trend.
55
Results for Step 4: Summary of Benefits and Limitations
There are multiple benefits to the use of total-impervious-area analysis as
a tool for evaluating the effectiveness of regulations that limit impervious
surfaces. For example, the data gathered as part of a total-impervious-area
analysis can be used to set benchmarks for specific areas. The ability to set
benchmarks allows for the effectiveness of regulations to be evaluated. In terms
of the use of aerial photos, it should be noted that they can be regularly acquired
via a relatively inexpensive data-gathering exercise. These photographs provide
information that can be used in conjunction with other temporally collected data.
This type of analysis also yields useful land-cover data, as shown in Chapter 5,
which can detect changes in a specific type of land-cover. In other words, it can
provide information relevant to other inquiries besides changes in impervious
area.
These benefits aside, there were some restrictions on the depth of the
evaluation that was possible for this thesis using the available data. The parcelspecific standards outlined in Thurston County’s regulations pertaining to
impervious surfaces could not be evaluated for their consistent application.
Therefore, no determination regarding whether they have been effectively
implemented was made as a part of this research effort. Yet, although this study
does not investigate the question at the parcel-scale, a more comprehensive study
that considers implications of permit conditions could be undertaken with access
to higher resolution photographs and multi-spectral imagery over a finite time
period. A study that normalizes for other variables (economic, social, and
56
political) would more closely evaluate the regulatory effects on increases in
impervious surfaces. (Cinde Donoghue: Personal Communication, 2007)
Recommendations
The existing regulations have not prevented the amount or rate of
impervious surfaces from increasing, which suggests that additional measures are
necessary to at least reduce the rate at which land is being converted to
impervious surfaces within the study area. One option is the creation of specific
zoning districts that further restrict the amount of impervious surface allowed for
each parcel. These districts could be applied to drainage basins containing
environmentally sensitive areas, in order to limit the amount of development or
impervious surfaces allowed within those areas. Another option is the adoption of
more restrictive environmental designation areas via the adoption of amendments
to the Thurston County Shoreline Master Program. Either of these options could
require specific caps on the amount of impervious area allowed, either on each
parcel or on a cumulative basis for the entire area. To further increase the
protection of ecosystems throughout Thurston County, the environmental
designation areas mentioned above could be incorporated into the County’s
Comprehensive Plan or Critical Areas Ordinance, in order to extend their range to
lands outside of Thurston County’s shoreline regions.
In addition to the adoption of more restrictive regulations, Thurston
County should explore partnerships with other organizations and government
agencies. Through these partnerships, resources could be pooled to support a
57
combined effort aimed at informing the general public of the reasons behind the
need for impervious surface limitations. A public education and outreach
campaign would help build support for more restrictive regulations. This type of
support is vital, as the County attempts to balances the Growth Management Act’s
planning goals, and the economic and private property interests of its citizens.
The County also needs to invest in staff, data, and technology that will
allow for the parcel-level research mentioned above to take place. This type of
information is vital to policy makers and citizens so that they can evaluate how
successfully regulations have fulfilled their objectives. Improvements to data
availability and storage techniques should also be sought, in order to improve the
sharing of data from one department to another. In general, there is a need for a
central location for Thurston County’s physical and environmental condition data
that could house information used by State Agencies, Non-Governmental
Organizations and Thurston County’s individual departments.
Conclusion
The results of this thesis’ research indicate that: 1) the amount of
impervious surface present within Black Lake’s 200 foot shoreland area has
steadily increased from 1937 to 2005; 2) The primary regulations utilized by
Thurston County to limit impervious surfaces are those mandated by the
Shoreline Management Act (implemented in 1976) and the Growth Management
Act (implemented in 1995); 3) Thurston County’s regulations have not lowered
the growth rate of impervious surfaces within the study area; and 4) Total
58
impervious area analysis data can be used to successfully evaluate how effectively
regulations limit increases in impervious surfaces. This thesis found that
additional regulations need to be adopted by Thurston County, or at the very least
existing regulations need to be made more restrictive in order to prevent the
continued increase in impervious surfaces within the study area. In conclusion,
additional analysis needs to be done on a County-wide basis to determine how
effectively Thurston County’s regulations are limiting increases in impervious
surfaces. Efforts to inform the public regarding the hazards associated with
increases in impervious surfaces also need to be implemented.
59
References
Alberti, M., et al. 2006. The impact of urban patterns on aquatic ecosystems: An
empirical analysis in Puget lowland sub-basins. Journal of Landscape and Urban
Planning, date of issue: 10.1016/j.landurbplan.2006.08.001.
Arnold, C.L., and C. J. Gibbons. 1996. Impervious surface coverage: the
emergence of a key environmental indicator. Journal of the American Planning
Association 62(2): 243-258.
Booth, D.B. 1991. Urbanization and the natural drainage system – impacts,
solutions, and prognosis. The Northwest Environmental Journal 7:93-118.
Booth, D.B., and C. R. Jackson. 1997. Urbanization of Aquatic SystemDegradation Thresholds, Stormwater Detention, and the Limits of Mitigation.
Journal of the American Water Resources Association 22: 1-18.
Booth, D.B. 2000. Forest Cover, Impervious-Surface Area, and the Mitigation of
Urbanization Impacts in King County, Washington: Prepared for King County
Water and Land Resources Division. Seattle, Washington.
Booth, D. B., et al. 2001. Urban Stream Rehabilitation in the Pacific Northwest:
Final Report to U.S. EPA. Center for Urban Water Resources, University of
Washington, Seattle Washington.
Donoghue, C. 2007. Thurston County Long Range Planning Department.
Personal Communication.
Gates, Tim. 2003. Introduction to the Shoreline Management Act. Washington
State Department of Ecology, PUB 99-113, Lacey, Washington.
Grant, J., W. Schroeer, B. Petersen, and M. O’Neill. 2000. Our built and natural
environments: A technical review of the interactions between land use,
transportation, and environmental quality. U.S. Environmental Protection
Agency, EPA 231-R-00-005, Washington D.C.
Hinman, Curtis. 2005. Low Impact Development: Technical guidance manual for
Puget Sound. Puget Sound Action Team, 05-03, Olympia, Washington.
Washington State University Pierce County Extension, Tacoma, Washington.
Karr, J.R. 1998. Rivers as sentinels: using biology of rivers to guide landscape
management. In: Naiman, R.J., Bilby. R. (Eds.). River Ecology and
management: Lessons from the Pacific Coastal Ecoregion. Springer, New York,
pp. 502-528.
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May, C.W., E. B. Welch, R.R. Horner, J.R. Karr, and B.W. Mar. 1997. Quality
Indices for Urbanization Effects in Puget Sound Lowland Streams: Final Report
for the Washington State Department of Ecology. Department of Civil
Engineering, Environmental Engineering and Science Water Resources Series
Technical Report No. 154, University of Washington, Seattle, Washington.
Municipal Research and Services Center of Washington. Comprehensive
Planning/Growth Management. [updated April 2007; cited August 2007].
Available from http://www.mrsc.org/subjects/planning/compplan.aspx.
National Water Quality Inventory: 1996 Report to Congress. 1998. U.S.
Environmental Protection Agency, Washington D.C.
NLCD Land Cover Classification System Key. 1999. United States Geologic
Survey.
Watershed Protection Research Monograph No.1: Impacts of Impervious Cover
on Aquatic Systems. 2003. The Center for Watershed Protection, Elliot City,
Maryland.
Thurston County. 1995a. Comprehensive Plan. Thurston County Planning
Department, Olympia, Washington.
Thurston County. 1995b. Comprehensive Plan: The City of Tumwater and
Thurston County Joint Plan. Thurston County Long Range Planning
Department, Olympia, Washington.
Thurston County. 1997. Development Code: Critical Areas Ordinance, Chapter
17.15. Thurston County Planning Department, Olympia, Washington.
Thurston County. 1994. Drainage Design and Erosion Control Manual. Thurston
County Waste and Water Management Department, Olympia, Washington.
Thurston County Geodata Center. Thurston County GIS data files. [updated
August 2007; cited August 2007]. Available from http://www.geodata.org
Thurston County. 1976. Shoreline Master Program. Thurston Regional Planning
Council, Olympia, Washington.
Thurston County. 2005. Water Resources: Annual Monitoring Report 2003 –
2005 Water Years. Thurston County Department of Environmental Health,
Olympia, Washington.
The Relationship of Land-Cover to Total and Effective Impervious Area:
Building input files for the hydrological simulation program – FORTRAN
61
(HSPF) model. 2003. Thurston Regional Planning Council, Olympia,
Washington.
Urbanization and Streams: Studies of Hydrologic Impacts. 1997. U.S.
Environmental Protection Agency, EPA 20460 841-R-97-009, Washington D.C.
Washington State History Link. Washington Legislature enacts Growth
Management Act on April 1, 1990. [updated 2007; cited August 2007]
Available from
http://www.historylink.org/essays/printer_friendly/index.cfm?file_id=7759.
Washington State. 1990. The Growth Management Act, RCW 36.70A
Washington State Legislature, Olympia, Washington.
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Washington State Legislature, Olympia, Washington.
Wissmar, R.C. 1993. The Need for Long-Term Stream Monitoring Programs in
Forest Ecosystems of the Pacific Northwest. Journal of Environmental
Monitoring and Assessment. 26:219-234.
62
Appendices
63
Appendix 1. Thurston County Comprehensive Plan: Chapter 9 – Natural
Environment
III. GOALS, OBJECTIVES AND POLICIES
A. GEOLOGIC HAZARD AREAS
GOAL: MINIMIZE THE LOSS OF LIFE AND PROPERTY FROM
LANDSLIDES AND SEISMIC, VOLCANIC, OR OTHER NATURALLY
OCCURRING EVENTS, AND MINIMIZE OR ELIMINATE LAND-USE
IMPACTS ON GEOLOGICALLY HAZARDOUS AREAS.
OBJECTIVE: To designate and manage geologic hazard areas to avoid loss of
life and damage to structures by guiding development away from geologic hazard
areas and by regulating uses and activities that occur within or near such areas in
a manner that minimizes the potential for damage or loss of life.
POLICIES:
1. The county should designate and provide for the protection and management of
geologic hazard areas based on best available science and cumulative
impact assessments of existing and planned land and resource uses within
and near geologic hazard areas.
2. The county should restrict development and resource use within or near areas
susceptible to significant damage from erosion, landslides, earthquakes or
lahar flows, as necessary to protect life, property, and wildlife habitats
(e.g., streams and marine waters downslope).
3. The county should cooperate with other jurisdictions and agencies to
implement the “Natural Hazards Mitigation Plan for the Thurston
Region,” TRPC 2003, or as hereafter amended.
4. The county should protect the public from natural hazards, minimize the need
for emergency rescues and replacement of public facilities damaged by
natural forces, and avoid public subsidy of private development located in
areas vulnerable to damage from natural events by minimizing the amount
of development at risk.
5. The county should delineate landslide hazards, the path of potential lahar flows,
and other natural hazard areas with the greatest degree of accuracy
possible. Reevaluate land-use regulations in light of the refined mapping
and make changes as warranted, consistent with public safety and best
available science.
6. The county should collaborate with other jurisdictions and agencies to gain a
better understanding of earthquake hazards in the county and devise
appropriate mitigative measures to minimize the loss of life and property.
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B. GROUNDWATER AND AQUIFER RECHARGE AREAS
GOAL: PROTECT Groundwater QUALITY AND QUANTITY.
OBJECTIVE: To provide for the identification and protection of sensitive
aquifer recharge areas, protect groundwater quality, and prudently conserve
groundwater resources.
POLICIES:
1. The county should designate and provide for the protection and management of
groundwater and aquifer recharge areas based on best available science
and cumulative impact assessments of existing and planned future land
and resource uses within and near aquifer recharge areas.
2. The county should protect groundwater quality and prevent aquifer
contamination, degradation, and depletion through the comprehensive
management of groundwater in conformance with the Clean Water Act,
the Northern Thurston County Ground Water Management Plan, the South
Thurston County Aquifer Protection Strategy, and all other applicable
federal, state and local water quality regulations.
3. The county should determine, based on watershed plans, if there are areas
where low summer stream flows or elevated instream water temperature
may, now or in the future, imperil anadromous or native resident fish. If
such areas are identified, the county should devise and implement
development restrictions and management practices as necessary to sustain
the fish.
4. The county should reduce allowed land-use densities, in areas where the supply
of groundwater is limited, to the extent necessary to preserve sufficient
water for existing uses, unless alternative domestic water supplies are
available from other sources. Special consideration should be given to
areas where additional groundwater withdrawals would diminish summer
stream flows and elevate instream water temperatures and thereby
jeopardize the survival of anadromous or native resident fish.
5. The county should regulate land-uses within designated wellhead protection
areas to prevent degradation of groundwater quality.
6. The county should strive to develop and fully implement regional wellhead
protection policies and locally developed wellhead protection plans.
Support efforts by water utilities to acquire or provide long-term
management of wellhead protection areas.
7. The county should encourage that coordinated, reliable water systems be used
to provide water in the urban growth areas. Urge jurisdictions to develop
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compatible, coordinated water system design standards for their growth
areas.
8. The county should discourage construction and use of individual private wells
in urban growth areas where community or public water sources are
reasonably and economically available.
9. The county should encourage the use of community or public water in
unsewered areas where residential density is in excess of one unit per acre.
Community or public water systems should also be provided in residential
developments with densities in excess of one unit per two acres and
excessive soil permeability.
10. The county should ensure that community and public water systems and
supplies are managed to meet state and local health standards.
11. The county should regularly monitor and protect the water quality of
watersheds feeding into water bodies used for drinking water (e.g.,
Summit Lake). If pollution is identified, the county should devise and
implement programs to improve water quality.
12. The county should encourage the safe recycling and reuse of water and treated
wastewater in order to recharge aquifers, conserve groundwater supplies,
and reduce contamination of receiving waters.
13. The county should encourage the use of no- and low-water use appliances and
fixtures, particularly in conjunction with septic systems, to reduce the
potential for groundwater contamination.
14. The county should promote the use of integrated pest management and the
reduction of pesticide and fertilizer use by residents, businesses, and
governmental agencies in designated wellhead protection areas and in
areas identified as a source of contamination to important wildlife habitats
and shellfish beds.
C. SURFACE WATER
GOAL: PROTECT AND IMPROVE THE WATER QUALITY AND
BIOLOGICAL HEALTH OF LAKES, WETLANDS, RIVERS, STREAMS,
AND PUGET SOUND.
OBJECTIVE 1: To manage surface water in a manner that will protect or
improve the quality of water sustaining human use, wildlife, and aquatic life.
POLICIES:
1. The county should provide for the protection and management of surface water,
consistent with the Clean Water Act, based on best available science and
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cumulative impact assessments of existing and planned future land and
resource uses within the watersheds.
2. The county should retain substantially in their natural condition: ponds,
wetlands, rivers, lakes and streams, and their associated buffers and
riparian areas.
3. The county should protect streams from the adverse impacts of activities
occurring within their watersheds to avoid degradation of their water
quality and biological health. These impacts include, but are not limit to,
elevation of stream water temperature and low flows in summer and
stream channel damage and sedimentation from excessive flows during
winter.
4. The county should protect and maintain the valuable natural functions of
wetlands by maintaining an undisturbed or restored native vegetation
buffer around the wetland and by prohibiting filling, draining, and clearing
within wetlands and their associated buffers.
5. The county should designate and protect riparian habitat areas to help maintain
water quality consistent with best available science. (Also see related
policies under Section E, Important Fish, Wildlife, and Plant Habitat).
6. The county should prevent development and activities in streams, riparian
areas, and wetlands and any associated buffers that would damage water
quality or habitat functions, except to the minimum extent necessary when
there is no reasonable alternative for accommodating an essential use (e.g.,
an essential road or utility crossing).
7. The county should consider establishing a wetland mitigation bank to provide
an alternative to individual stream and wetland mitigation projects
associated with essential public projects. Enhancement of degraded
wetlands is preferred over creation of new wetlands.
8. The county should require, to the extent legally permissible, restoration of
degraded buffers and wetlands associated with lakes, streams, rivers, and
Puget Sound as a part of new land-uses and development activity.
9. The county should cooperate with adjoining jurisdictions to develop
complementary regulations pertaining to streams, upland wildlife habitat,
and other Critical Areas that span jurisdictional boundaries.
10. The county should evaluate the performance of county regulations in
maintaining surface water and monitor the performance of restoration and
enhancement projects to provide a basis for periodic refinement of county
regulations and management practices.
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11. The county should promote the use of integrated pest management, reduction
of pesticide and fertilizer use, and best management practices for animal
waste by residents, businesses, and governmental agencies in areas
identified as a source of contamination of surface water, particularly if it
affects the harvest of shellfish.
12. The county should provide technical assistance and education, to the extent
resources allow, to operators of small businesses and industrial uses, and
residents located near surface water bodies regarding proper storage,
handling and disposal of hazardous materials.
13. The county should encourage the Thurston Conservation District Board to
continue their voluntary efforts regarding education, conservation
planning, and use of best management practices on existing farms, golf
courses, parks, schools, residences, and other facilities that use pesticides
and fertilizers near surface water bodies.
OBJECTIVE 2: Lake Management - To provide for a comprehensive, long-term
approach to lake management that accommodates all appropriate uses and
benefits, consistent with the maintenance or enhancement of water quality.
POLICIES:
1. The county should work with property owners and interested parties to develop
an integrated aquatic management plan for lakes, consistent with best
available science and the Clean Water Act, that addresses pollution
sources, such as stormwater runoff and on-site disposal system effluent,
and the cumulative impacts of existing and planned future land and
resource uses within the watersheds.
2. The county should strive to reduce the spread of Eurasian milfoil and other
exotic aquatic weeds through monitoring, public information and other
means.
OBJECTIVE 3: Marine Waters and Shoreline Management - To preserve and
protect marine shorelines and near shore areas as valuable natural resources and
habitats, consistent with state and federal law.
POLICIES:
1. The county should regulate uses and activities along the marine shoreline and
within the waters of Puget Sound, consistent with the State Shoreline
Management Act and the Clean Water Act, based on best available science
and cumulative impact assessments of existing and planned future land
and resource uses in upland watersheds.
2. The county should identify and protect, consistent with best available science,
important, sensitive marine habitats, such as juvenile salmon migration
corridors, kelp and eelgrass beds, shellfish beds, and herring and smelt
spawning areas.
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3. The county should protect special shoreline features, such as dry accretion
beaches, and undeveloped bays and lagoons.
4. The county should provide information to property owners regarding various
protection options for their marine shoreline consistent with the State
Shoreline Management Act and the Shoreline Master Program for the
Thurston Region. Encourage the use of “bioengineered” shoreline
stabilization as an alternative to bulkheading or other forms of shoreline
armoring where necessary to protect existing structures from erosion.
D. FREQUENTLY FLOODED AREAS
GOAL: PROTECT LIFE AND STRUCTURES FROM FLOOD HAZARDS
AND RETAIN THE FLOOD STORAGE, TRANSMISSION CAPACITY, AND
HABITAT VALUE OF FLOODPLAINS.
OBJECTIVE: To provide the highest degree of flood protection at the least cost.
POLICIES:
1. The county should provide the highest degree of flood protection at the least
cost through identification and accommodation of natural flooding and
channel migration processes that pose hazards to life or property.
Protection and management should be based on best available science and
cumulative impact assessments of existing and planned future land and
resource uses within the floodplains, channel migration zones, and
watersheds.
2. The county should prohibit development and emplacement of fill in floodways
and floodplains, except to the minimum extent necessary to accommodate
public infrastructure and utilities that cannot be accommodated elsewhere
and to stabilize channels against erosion in order to protect existing
agricultural lands, public roads and bridges, public infrastructure, utilities
and significant private structures, and to achieve habitat enhancement.
Any development in the floodways should be designed to avoid habitat
degradation. Stream bank stabilization, if necessary, should be of a type
that maintains or enhances habitat functions. Rip-rap and other hard
armoring should only be used if there is no effective alternative, based on
sound engineering principles, to protect existing structures or public
facilities.
3. The county should provide for land-uses such as forestry, open space, public
recreation, existing agriculture and water-dependent uses in areas subject
to river flooding to minimize risks to life and structures and help retain or
enhance habitat functions. Other uses and development in the floodplain
should be restricted to minimize public safety risks (e.g., through
compensating design features) and loss of habitat function.
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4. The county should minimize disruption of long-term stream channel migration
processes that allow formation of essential habitat features by prohibiting
construction of new structures in channel migration zones and minimizing
streambank stabilization.
5. The county should actively participate in the multi-jurisdictional flood hazard
reduction efforts within the Chehalis River Basin.
6. The county should regulate uses in and around areas where groundwater
periodically surfaces as necessary to avoid property damage and protect
groundwater quality.
7. The county should maintain the county's enrollment in the Community Rating
System through the National Flood Insurance Program.
E. IMPORTANT FISH, WILDLIFE, AND PLANT HABITAT
GOAL: PROTECT, CONSERVE, AND ENHANCE THE ECOLOGICAL
FUNCTIONS OF IMPORTANT FISH, WILDLIFE, AND PLANT HABITATS.
OBJECTIVE: Identify important fish, wildlife, and plant habitats and develop
strategies for protecting or restoring important habitats, particularly if they are at
risk of significant degradation.
POLICIES:
1. The county should protect fish and wildlife habitats that are important to the
long-term viability of locally important species in Thurston County, which
are unique or rare, or which contain state priority species or species listed
under the federal Endangered Species Act.
2. The county should identify and protect (e.g., through easements, fee
acquisition, or regulations) land providing essential connections between
riparian habitat areas, open spaces, and significant wildlife habitats
sustaining state priority, federally listed, or locally important wildlife
species. Include wildlife corridors that lead away from riparian areas to
facilitate wildlife migration to upland habitats and minimize the potential
for increased fecal contamination of streams from wildlife sources.
3. The county should encourage protection of areas containing special plants and
special plant communities listed by the state Department of Natural
Resources Heritage Program.
4. The county should establish and protect riparian habitat areas to maintain or
enhance the functions sustaining aquatic life and terrestrial wildlife,
consistent with best available science.
70
5. The county should establish priorities for performing stream/subwatershed
assessments to tailor and refine riparian habitat widths, consistent with
best available science, to provide appropriate water quality and habitat
protection while minimizing the burden on affected property owners.
Priority should be given to those areas at greatest risk of degradation, for
example, due to potential impacts from existing and planned development,
the sensitivity of dependent species, or the sensitivity of the watershed’s
hydrology to development.
6. The county should evaluate streams/riparian areas supporting anadromous fish,
sensitive native resident fish, or state priority wildlife species to determine
their long-term viability to sustain such fish and wildlife at buildout of the
drainage basin under current regulations, consistent with best available
science. The county should build upon the information and analysis
produced through the Watershed Resource Inventory Area projects as
necessary to assess current and projected stream and riparian conditions.
In performing the assessments, consider factors such as stream gradient,
channel dimensions, valley configurations, historical conditions, current
stream conditions, the width, continuity and quality of riparian areas, the
presence of any associated wetlands, aquatic and terrestrial habitat
utilization and sensitivity, the intensity of adjacent uses, current zoning,
the cumulative impacts of existing and planned future land and resource
use, subwatershed hydrology (e.g., based on soil characteristics, tree
cover, land-use types and characteristics, impervious surface coverage,
and the performance of existing stormwater facilities), and water quality.
If any streams/riparian areas that currently support anadromous fish,
sensitive native resident fish, or state priority wildlife species would not be
expected to sustain such fish and wildlife at buildout of the subwatershed
under current zoning and development regulations, the county should
identify and pursue viable remedial actions to preserve or enhance the
habitat functions (e.g., maintaining water quality). Remedial actions may
include, for example, limits on effective impervious surface coverage and
retention of substantial tree cover in the subwatershed, higher stormwater
standards, reduced housing density, limits on stream crossings by roads or
utility lines to maintain the continuity of riparian areas, expanded riparian
areas, and restoration.
7. The county should identify priorities for fish and wildlife habitat
protection/acquisition and other remedial actions necessary to maintain or
restore the riparian or important upland habitat. Consider giving highest
priority for habitat protection/acquisition to the following:
a. streams/riparian areas with sensitive fish or wildlife species in
watersheds with existing or planned levels of development that threaten fish
and wildlife survival;
71
b. streams/riparian areas that support significant numbers of anadromous or
sensitive native resident fish in drainages with moderate levels of
development which, based on best available science, have potential to be
maintained or restored if prompt action is taken;
c. streams/riparian areas largely in a natural condition that support the
county’s largest or most sensitive populations of Chinook, coho or chum
salmon, steelhead, cutthroat trout or other native fish, particularly if they
are listed as endangered or threatened species; and
d. streams/riparian areas that support sensitive populations of priority
wildlife species or significantly affect shellfish beds subject to harvest
restrictions or closures.
8. The county should provide for removal of existing “man made” barriers to
anadromous fish migration in streams (e.g., impassible culverts) and
prohibit installation of new barriers.
9. The county should preserve adequate water quantity and quality for fish
migration, spawning, incubation and rearing, including peak and summer
flow levels, dissolved oxygen and chemical content, sediment load, and
temperature.
10. The county should maintain and improve surface water quality, consistent
with the Clean Water Act, such that pollution does not imperil public
health or the survival of fish, shellfish, or other aquatic life or prevent the
harvest of shellfish. Surface waters within the drainage basins of
Geological Sensitive Areas, and areas of significant recreational or
commercial shellfish harvesting should be maintained or restored to the
highest quality possible.
11. The county should prohibit uses and activities that degrade lakes, streams and
shellfish beds or result in the loss of the natural functions of waterbodies,
wetlands, and groundwater aquifers.
12. The county should require that sewage treatment plant owners explore
opportunities for the beneficial use of treated wastewater before any new
point discharges are authorized. The county should prohibit any new
wastewater discharges, including those from sewage treatment plants, into
waters where shellfish are harvested, if the discharges would significantly
harm the shellfish or their harvest potential.
13. The county should cooperate with adjoining jurisdictions to develop
complementary regulations pertaining to streams, fish, wildlife, plant
habitats, and other Critical Areas that span jurisdictional boundaries.
14. The county should prevent development and activities in streams, riparian
areas, wetlands, other protected wildlife habitats and any associated
72
buffers that would damage their functions, except to the minimum extent
necessary when there is no reasonable alternative for accommodating an
essential use (e.g., an essential road or utility crossing).
15. The county should encourage stream and wetland restoration activities
consistent with best available science through partnerships between the
county, conservation district, other agencies, and landowners. Provide
incentives for landowners to retain, enhance, or restore important wildlife
habitat such as reduced permit fees, expedited permit review, and
reduction in property taxes.
F. GREENSPACES
GOAL: IDENTIFY AND PROTECT IMPORTANT GREENSPACES USEFUL
FOR RECREATION, TRAILS, WATER RESOURCE PROTECTION OR
WHICH CONTAIN IMPORTANT WILDLIFE HABITATS.
OBJECTIVE 1: Important Greenspaces Designation – To provide for
identification of important greenspaces within and adjacent to Thurston County,
consistent with state law.
POLICIES:
1. The county should periodically update the Important Greenspaces Map (Map
31) to accurately reflect current conditions and knowledge regarding sites,
open space corridors (including corridors within and between urban
growth areas), and ecological units which are useful for recreation, trails,
or water resource protection, contain important wildlife habitats and
species, or provide connections to Critical Areas that would be useful for
wildlife travel or dispersal.
2. The county should coordinate greenspaces planning with important greenspaces
stakeholders (e.g., tribes, federal agencies, state departments, county
departments, adjacent jurisdictions, private conservation organizations,
local land trusts, resource land owners, county residents and other
interested parties.)
3. The county should support greenspaces planning efforts by important
greenspaces stakeholders within or adjacent to Thurston County.
4. The county should provide for extensions of urban trails that have been
identified by an adjacent jurisdiction, consistent with the Important
Greenspaces Map (Map 31). However, important wildlife habitats,
including riparian areas, should have priority over trails. Therefore, locate,
design, and construct trails to avoid significantly degrading important
wildlife habitats or disrupting their use by state priority or federally
protected wildlife species.
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OBJECTIVE 2: Protection Options - Use a variety of protection options in order
to protect the greatest number of priority greenspaces.
POLICIES:
1. The county should establish a system for identifying and prioritizing
greenspaces for acquisition or other form of protection in order to
maximize public benefits. The following types of lands should be
considered for acquisition:
a. lands important to public health and safety, such as critical aquifer
recharge areas for public drinking water supplies, wellhead
protection areas, flood prone areas, geologically hazardous areas,
and sensitive and priority watersheds defined in adopted basin
plans;
b. lands containing environmental features with significant educational,
scientific, wildlife habitat (especially areas important to the
preservation of anadromous fish), natural or historic values;
c. lands that provide access to fresh and marine waters;
d. lands with recreational values, such as sites with potential to
accommodate picnicking, boating, fishing, swimming, camping,
trail use, nature observation, play areas and sports fields, or open
space corridors within and between urban growth areas, consistent
with the Important Greenspaces Map (Map 31); and
e. lands that provide scenic amenity or community identity.
2. The county should identify and evaluate the protection options for each
important greenspace. Preservation options should include, but not be
limited to: critical area designation (where appropriate), clustered
development, enrollment in the open space tax program, conservation
easements, purchase or transfer of development rights, and public
acquisition.
3. The county should provide for identification and preservation of important
greenspaces in coordination with the acquisition and development of
future county parks, trails, preserves, and water resource protection areas.
4. The county should encourage private property owners to protect important
greenspaces through the clustering of development on the least sensitive
portion of the property.
5. The county should encourage private property owners with priority resources,
according to the Public Benefit Rating System, to enroll their properties in
the Open Space Tax Program.
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6. The county should support efforts by land trusts and conservation organizations
to acquire either fee simple property for preserves or conservation
easements on private lands serving important habitat or water quality
functions, protecting critical areas, or identified on the Important
Greenspaces Map (Map 31).
7. The county should support efforts to protect lands identified in the Washington
Department of Natural Resources Natural Heritage Data Base, through
either private initiatives or public acquisition.
8. The county should support efforts by other governmental agencies to acquire
and develop parks, trails or preserves within or adjacent to Thurston
County, consistent with adopted park plans, the Important Greenspaces
Map (Map 31), and the preservation of important wildlife habitat.
9. The county should examine, and act on as appropriate, opportunities to develop
operating agreements and/or leases for land in proximity to urbanizing
areas that are appropriate for preservation as open space, nature study
areas or conservation areas.
10. The county should develop liaison with the Nature Conservancy, land trusts
and other organizations and agencies interested in acquisition of lands for
conservation and preservation.
11. The county should require, to the extent legally permissible, that areas for
active recreation or open space be dedicated as part of the development
approval process for residential developments containing ten or more
acres that are zoned for more than one residential dwelling unit per acre,
based on the demand expected to be generated by the developments for
such areas.
12. The county should consider amending the open space program enrollment
criteria to enable enrollment of parcels of less than five acres that contain
important wildlife habitat, consistent with Chapter 84.34 RCW.
13. The county should encourage the use of special incentives to preserve and
protect high quality or sensitive environmental resources that regulations
do not adequately protect or to minimize the burden of affected private
property owners. The means to be used (in order of priority) include: open
space taxation, the assistance of federal or state resource agencies, the
initiatives of private conservation organizations and local land trusts, or
public acquisition.
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G. AIR QUALITY
GOAL: protect and improve the county's air quality and minimize OR
ELIMINATE ODOR AND noise from new land-uses that would reduce the
livability of residential areas OR SIGNIFICANTLY DEGRADE IMPORTANT
WILDLIIFE HABITAT.
OBJECTIVE: To protect the livability of established neighborhoods and to
protect sensitive wildlife habitats.
POLICIES:
1. The county should support federal, state, and regional clean air policies and air
quality standards and regulations.
2. The county should assess the impacts of new land-uses and activities on air
quality, including pollution, particulate matter, odor and noise. The county
should direct those uses that are likely to generate health or nuisance
problems away from residential neighborhoods, schools, hospitals, and
facilities housing residents who are particularly susceptible to air quality
problems (e.g., long-term health care centers), and wildlife refuges.
3. The county should maintain the peace and quiet of residential neighborhoods
by:
a. limiting noisy, polluting, or heavy traffic generating land-uses and
activities in close proximity to such areas;
b. through the use of screens, open space, or other buffers; and
c. through enforcement of noise and air emission standards.
4. The county should minimize the noise impacts from noise-producing sources,
such as airports and military firing ranges, by designating noise impacted
lands for use as forestry, agriculture, public reserves, industrial and, as a
last priority, low density residential. Require that the deed, title, or
covenants for lots in new residential subdivisions contain statements
notifying prospective purchasers that the property will be affected by
noise.
5. The county should continue to coordinate with local and regional government
agencies to reduce air pollution by adopting land-use and transportation
plans that help reduce the amount of vehicle emissions.
6. The county should provide education and information to the public to promote
reduction of air pollutants and particulate matter.
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H. MANAGEMENT APPROACHES
GOAL: ENCOURAGE COMPREHENSIVE, SCALE-APPROPRIATE
APPROACHES TO ENVIRONMENTAL RESOURCE MANAGEMENT AND
COORDINATION OF MANAGEMENT ACTIONS.
OBJECTIVE 1: Management Approaches- To encourage and facilitate
coordination of resource management to enable efficient use of public funds,
maximize environmental and public benefits through coordinated and
complementary actions, and to facilitate work at the appropriate scale (e.g.,
subwatershed).
POLICIES:
1. The county should establish management approaches that reflect our
dependence on natural systems and maintain a balance between human
uses and the natural environment.
2. The county should establish a pattern and intensity of land and resource use
that are consistent with the limitations imposed by natural constraints
(e.g., flooding, steep slopes prone to landslides, and saturated soil
conditions), sustain environmental functions (e.g., aquifer recharge, water
storage and cleansing performed by wetlands), and minimize public safety
risks.
3. The county should assess the cumulative impacts of past, current, and planned
future land and resource uses on the county’s natural environment and
implement management and protection programs that address these
impacts.
4. The county should incorporate in management approaches, education
programs; the use of incentives; regulation; restoration; construction;
maintenance; county or land trust acquisition; and adaptive management,
including establishing performance goals and monitoring programs, to
enable evaluation of the effectiveness of implemented regulations and
programs.
5. The county should provide for management at the appropriate scale (e.g.,
subwatershed), take into account the many factors and interests involved,
and draw upon best available science.
6. The county should select a management approach that best addresses the
degree of risks or hazards to the public, the uniqueness and sensitivity of
the resource, and the long-term public benefit and the cost and financing
feasibility.
7. The county should designate and manage Critical Areas in a manner that will
sustain dependent human and wildlife use and avoid loss of life and
damage to structures.
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OBJECTIVE 2: Water Resource Management Approaches – To coordinate
water resources planning, funding and implementation within Thurston County to
ensure high quality surface and groundwater, preserve the functions of water
resources, ensure compatibility between land and water uses and minimize the
costs of parallel programs.
POLICIES:
1. The county should manage county-wide water resources through a coordinated
water resources program that integrates county groundwater, stormwater,
lakes, stream and wetland programs related to water quantity and quality.
2. The county should consider the hydrologic continuity between ground and
surface water when managing water resources.
3. The county should address water resource concerns by the appropriate scale,
such as a catchment, subwatershed or sub-basin for surface waters and by
aquifers for groundwater.
4. The county should support watershed planning processes conducted under
RCW 90.82 as a framework for comprehensive water resource
management.
5. The county should involve affected stakeholders in groundwater, watershed and
stormwater basin planning.
6. The county should support and implement the county-adopted water resource
plans addressing watersheds, stormwater, sewerage, groundwater, water
supply and solid waste, including the Northern Thurston County Ground
Water Management Plan and the South Thurston County Aquifer
Protection Strategy.
7. The county should protect public water supplies from contamination to avoid
the cost of developing new water sources.
8. The county should manage water resources for multiple beneficial uses. Use for
one purpose should preserve opportunities for other uses, while
maintaining overall water quality. When conflicts arise, the natural system
should be given priority, particularly if the use would be detrimental to
anadromous fish or public safety.
9. The county should monitor both surface water and groundwater to evaluate
program effectiveness, establish long-term trends for both water quality
and water quantity, and provide for the early detection of pollution, to
minimize the damage and the cost of resource restoration, and to provide a
basis for adaptive management.
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8. The county should identify and designate in the Critical Areas regulations
geographic areas with unusual physical features or high sensitivity to
human impacts that require management approaches specially designed
for each area.
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Appendix 2. The City of Tumwater and Thurston County Joint Plan: Goal
#6 Policy Objectives
Policy Objective
6.1
Ensure that new development is in conformance with the requirements and
standards of the North Thurston Groundwater Protection Plan.
6.2
Ensure that new development is in conformance with the requirements and
standards of the City of Tumwater’s Master Storm Drainage Plan.
6.3
Ensure that new development meets the quality and quantity control
requirements contained in the Drainage Design and Erosion Control
Manual for the Thurston Region.
6.4
Ordinances meeting applicable legal standards should be adopted by the
City of Tumwater and Thurston County regulating land-uses within
wellhead protection areas to ensure that negative effects on groundwater
quality are avoided or mitigated.
6.5
Ensure that future land-use and development is in conformance with
regional wellhead protection policies and adopted wellhead protection
programs of Thurston County and the City of Tumwater.
6.6
Ensure coordination with the Percival Creek Comprehensive Drainage
Basin Plan.
6.7
Ensure that new development is in conformance with aquifer protection
standards of the City’s Conservation Plan.
6.8
Prohibit new residential development in the 100-year floodplain.
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Appendix 3. The City of Tumwater and Thurston County Joint Plan: Goal
#8 Policy Objectives
8.1
Ensure that new development is in conformance with the applicable
standards and requirements for critical areas
8.1.1
Conduct a geological study and mapping program for the urban
growth area.
8.2
Prohibit or set conditions on development based on anticipated adverse
environmental impact.
8.3
Inventory the hillside areas to determine which areas, because of known
hazards, topographic formations and unstable soils, should be limited to
extent of development.
8.3.1
Conduct a geological study and mapping program for the urban
growth area.
8.4
Development within the Shoreline Management Jurisdiction shall adhere
to the flood control policies, land-use controls and regulations of the
applicable environmental designation as described in the Thurston Region
Shoreline Master Program adopted by the City of Tumwater and Thurston
County.
8.5
Consider applying the standards of the City’s Tree Protection Ordinance to
the unincorporated urban growth area through an intergovernmental
agreement.
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Appendix 4. NLCD Land-Cover Classification System Land-Cover Class
Definitions
Water – All areas of open water or permanent ice/snow cover.
11. Open Water – All areas of open water; typically 25 percent or greater cover of
water (per pixel).
12. Perennial Ice/Snow – All areas characterized by year-long cover of ice and/or
snow.
Developed – Areas characterized by a high percentage (30 percent or greater) of
constructed materials (e.g. asphalt, concrete, buildings, etc).
21. Low Intensity Residential – Includes areas with a mixture of constructed
materials and vegetation. Constructed materials account for 30-80 percent of the
cover. Vegetation may account for 20 to 70 percent of the cover. These areas
most commonly include single-family housing units. Population densities will be
lower than in high intensity residential areas.
22. High Intensity Residential – Includes highly developed areas where people
reside in high numbers. Examples include apartment complexes and row houses.
Vegetation accounts for less than 20 percent of the cover. Constructed materials
account for 80 to 100 percent of the cover.
23. Commercial/Industrial/Transportation – Includes infrastructure (e.g. roads,
railroads, etc.) and all highly developed areas not classified as High Intensity
Residential.
Barren – Areas characterized by bare rock, gravel, sand, silt, clay, or other earthen
material, with little or no “green” vegetation present regardless of its inherent
ability to support life. Vegetation, if present, is more widely spaced and scrubby
than that in the “green” vegetated categories; lichen cover may be extensive.
31. Bare Rock/Sand/Clay – Perennially barren areas of bedrock, desert, pavement,
scarps, talus, slides, volcanic material, glacial debris, beaches, and other
accumulations of earthen material.
32. Quarries/Strip Mines/Gravel Pits – Areas of extractive mining activities with
significant surface expression.
33. Transitional – Areas of sparse vegetative cover (less than 25 percent of cover)
that are dynamically changing from one land-cover to another, often because of
land-use activities. Examples include forest clearcuts, a transition phase between
forest and agricultural land, the temporary clearing of vegetation, and changes due
to natural causes (e.g. fire, flood, etc.).
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Forested Upland – Areas characterized by tree cover (natural or semi-natural
woody vegetation, generally greater than 6 meters tall); tree canopy accounts for
25-100 percent of the cover.
41. Deciduous Forest – Areas dominated by trees where 75 percent or more of the
tree species shed foliage simultaneously in response to seasonal change.
42. Evergreen Forest – Areas dominated by trees where 75 percent or more of the
tree species maintain their leaves all year. Canopy is never without green foliage.
43. Mixed Forest – Areas dominated by trees where neither deciduous nor
evergreen species represent more than 75 percent of the cover present.
Shrubland – Areas characterized by natural or semi-natural woody vegetation
with aerial stems, generally less than 6 meters tall, with individuals or clumps not
touching to interlocking. Both evergreen and deciduous species of true shrubs,
young trees, and trees or shrubs that are small or stunted because of
environmental conditions are included.
51. Shrubland – Areas dominated by shrubs; shrub canopy accounts for 25-100
percent of the cover. Shrub cover is generally greater than 25 percent when tree
cover is less than 25 percent. Shrub cover may be less than 25 percent in cases
when the cover of other life forms (e.g. herbaceous or tree) is less than 25 percent
and shrubs cover exceeds the cover of the other life forms.
Non-natural Woody – Areas dominated by non-natural woody vegetation; nonnatural woody vegetative canopy accounts for 25-100 percent of the cover. The
non-natural woody classification is subject to the availability of sufficient
ancillary data to differentiate non-natural woody vegetation from natural woody
vegetation.
61. Orchards/Vineyards/Other – Orchards, vineyards, and other areas planted or
maintained for the production of fruits, nuts, berries, or ornamentals.
Herbaceous Upland – Upland areas characterized by natural or semi-natural
herbaceous vegetation; herbaceous vegetation accounts for 75-100 percent of the
cover.
71. Grasslands/Herbaceous – Areas dominated by upland grasses and forbs. In
rare cases, herbaceous cover is less than 25 percent, but exceeds the combined
cover of the woody species present. These areas are not subject to intensive
management, but they are often utilized for grazing.
Planted/Cultivated – Areas characterized by herbaceous vegetation that has been
planted or is intensively managed for the production of food, feed, or fiber; or is
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maintained in developed settings for specific purposes. Herbaceous vegetation
accounts for 75-100 percent of the cover.
81. Pasture/Hay – Areas of grasses, legumes, or grass-legume mixtures planted
for livestock grazing or the production of seed or hay crops.
82. Row Crops – Areas used for the production of crops, such as corn, soybeans,
vegetables, tobacco, and cotton.
83. Small Grains – Areas used for the production of graminoid crops such as
wheat, barley, oats, and rice.
84. Fallow – Areas used for the production of crops that are temporarily barren or
with sparse vegetative cover as a result of being tilled in a management practice
that incorporates prescribed alternation between cropping and tillage.
85. Urban/Recreational Grasses – Vegetation (primarily grasses) planted in
developed settings for recreation, erosion control, or aesthetic purposes.
Examples include parks, lawns, golf courses, airport grasses, and industrial site
grasses.
Wetlands – Areas where the soil or substrate is periodically saturated with or
covered with water as defined by Cowardin et al.
91. Woody Wetlands – Areas where forest or shrubland vegetation accounts for
25-100 percent of the cover and the soil or substrate is periodically saturated with
or covered with water.
92. Emergent Herbaceous Wetlands – Areas where perennial herbaceous
vegetation accounts for 75-100 percent of the cover and the soil or substrate is
periodically saturated with or covered with water.
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Adair_CMESThesis2007.pdf