Bothell, Washington Urban Tree Canopy Assessment Report

An Assessment of Urban Tree Canopy in the City of Bothell, Washington

Prepared By Plan-It Geo, LLC, Arvada, Colorado

Prepared For King Conservation District and The City of Bothell, WA

Pa ge left intent ionally blank < A L L O W S L AYO U T V I E W I N WO R D. D E L E T E P R I O R T O PUBLISHING>

An Assessment of Urban Tree Canopy in the City of Bothell, WA March 2016

Prepared By Plan-It Geo, LLC, Arvada, Colorado

Acknowledgements This project was made possible by the King Conservation Districtâ&#x20AC;&#x2122;s Urban Forest Health Management and Stewardship Program In addition, special thanks go to Elizabeth Walker of the King Conservation District, and Daryn Brown for providing GIS data.

The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, sex, religion, age, disability, sexual orientation, marital status, family status, status as a parent (in education and training programs and activities), because all or part of an individualâ&#x20AC;&#x2122;s income is derived from any public assistance program, or retaliation.

Cover Photo Credits City of Bothell, WA Prepared by Plan-It Geo, LLC

Pa ge left intent ionally blank

CONTENTS EXECUTIVE SUMMARY .............................................................................................................................. 1 PROJECT FUNDAMENTALS & METHODOLOGY .......................................................................................... 3 MAPPING LAND COVER ..........................................................................................................................................................3 IDENTIFYING POSSIBLE PLANTING AND UNSUITABLE AREAS............................................................................................................3 VISUALIZING URBAN TREE CANOPY RESULTS...............................................................................................................................4 DEFINING ASSESSMENT LEVELS ................................................................................................................................................5 ASSESSMENT RESULTS & KEY FINDINGS ................................................................................................... 6 CITYWIDE LAND COVER ..........................................................................................................................................................6 CITYWIDE URBAN TREE CANOPY ..............................................................................................................................................6 PLANNING SUBAREAS .............................................................................................................................................................8 LAND USE ............................................................................................................................................................................9 SURFACE WATER MANAGEMENT AREAS ..................................................................................................................................10 SURFACE WATER SUBBASINS .................................................................................................................................................11 RIPARIAN AREAS .................................................................................................................................................................12 RIGHT-OF-WAY CITYWIDE ....................................................................................................................................................12 PARCELS ............................................................................................................................................................................13 RECOMMENDATIONS ............................................................................................................................. 14 RECOMMENDATION 1: UTILIZE ASSESSMENT RESULTS TO PRESERVE AND PROMOTE URBAN TREE CANOPY. ............................................14 RECOMMENDATION 2: DEVELOP AN URBAN FOREST MANAGEMENT PLAN TO PROVIDE A SHARED VISION. .............................................14 RECOMMENDATION 3: RELATE URBAN FORESTRY EFFORTS TO GREATER CITYWIDE INITIATIVES AND PRIORITIES. ......................................14 APPENDIX ............................................................................................................................................... 15 ACCURACY ASSESSMENT .......................................................................................................................................................15 COMPREHENSIVE ASSESSMENT AREA RESULTS ..........................................................................................................................17 City of Bothell, WA Geographic Summary: Planning Subareas ..................................................................................18 City of Bothell, WA Geographic Summary: Land Use .................................................................................................21 City of Bothell, WA Geographic Summary: Surface Water Management Areas ........................................................25 City of Bothell, WA Geographic Summary: Surface Water Subbasins ........................................................................28 City of Bothell, WA Geographic Summary: Riparian Areas ........................................................................................31 City of Bothell, WA Geographic Summary: Parcels ....................................................................................................34

FIGURES & TABLES FIGURES Figure 1: Bothell Location Map .............................................................................................................................................1 Figure 2: Five Primary Land Cover Classes generated from Aerial Imagery-based Analysis.................................................3 Figure 3: Sports Fields, Utility Easements, and Pioneer Cemetery, are considered unsuitable for planting .......................4 Figure 4: Examples of Relative Canopy Coverage by Parcel .................................................................................................4 Figure 5: Parcel Level Target Geography ..............................................................................................................................5 Figure 6: Rights-of-Way are the inverse of parcels ...............................................................................................................5 Figure 7: Planning Subareas within the Bothell City Limit ....................................................................................................5 Figure 8: Detailed Land Cover Classifications and Distribution ............................................................................................7 Figure 9: Percent of Urban Tree Canopy and Vegetated Possible Planting Area by Planning Subarea ................................8 Figure 10: UTC and PPA by Land Use ....................................................................................................................................9 Figure 11: Percent Urban Tree Canopy by Surface Water Management Area ...................................................................10 Figure 12: Percent Impervious Surface Area by Surface Water Management Area ...........................................................10 Figure 13: Highway Interchanges, Dense Housing Developments, and Agricultural Lands................................................11 Figure 14: Trees within the Right-of-Way near the Cityâ&#x20AC;&#x2122;s Municipal Court ........................................................................12 Figure 15: Percent Urban Tree Canopy by Parcel ...............................................................................................................13 Figure 16: Error Matrix for Land Cover Classifications within Bothell, WA ........................................................................16 Figure 17: Percent Urban Tree Canopy by Planning Subarea .............................................................................................19 Figure 18: Percent Possible Planting Area (Vegetation) by Planning Subarea....................................................................20 Figure 19: Land Use Categories ..........................................................................................................................................22 Figure 20: Percent Urban Tree Canopy by Land Use ..........................................................................................................23 Figure 21: Percent Possible Planting Area (Vegetation) by Land Use .................................................................................24 Figure 22: Percent Urban Tree Canopy by Surface Water Management Area ...................................................................26 Figure 23: Percent Possible Planting Area (Vegetation) by Surface Water Management Area .........................................27 Figure 24: Percent Urban Tree Canopy by Surface Water Subbasin ..................................................................................29 Figure 25: Percent Possible Planting Area (Vegetation) by Surface Water Subbasin .........................................................30 Figure 26: Percent Urban Tree Canopy by Riparian Area ...................................................................................................32 Figure 27: Percent Possible Planting Area (Vegetation) by Riparian Area ..........................................................................33 Figure 28: Percent Urban Tree Canopy by Parcel ...............................................................................................................34 Figure 29: Percent Possible Planting Area (Vegetation) by Parcel ......................................................................................35 TABLES Table 1: Generalized Land Cover Classification Results ........................................................................................................6 Table 2: Urban Tree Canopy Assessment Results .................................................................................................................6 Table 3: Top 3 Planning Subareas for Percent of Urban Tree Canopy ..................................................................................8 Table 5: Lowest 3 Surface Water Subbasins for Percent of Urban Tree Canopy ................................................................11 Table 6: Lowest 3 Riparian Areas for Percent of Urban Tree Canopy .................................................................................12 Table 7: Assessment Results by Citywide Right-of-Way .....................................................................................................12 Table 8: Planning Subarea Assessment Results ..................................................................................................................18 Table 9: Land Use Assessment Results ...............................................................................................................................21 Table 10: Surface Water Management Area Assessment Results ......................................................................................25 Table 11: Surface Water Subbasin Assessment Results......................................................................................................28 Table 12: Riparian Area Assessment Results ......................................................................................................................31

EXECUTIVE SUMMARY The City of Bothell is located in both King and Snohomish Counties northeast of Seattle, Washington. According to estimates from the U.S. Census Bureau’s Population Division, Bothell has grown from 33,613 people in 2010 to 41,630 people in 2015, representing an 8.8 percent increase. These Bothell residents have stressed the importance of “achieving harmony between the built and natural environments”, a “commitment to the conservation of scarce natural resources”, and the “protection of native wildlife habitats”, as expressed in the revised Imagine Bothell… Comprehensive Plan (adopted in 2015). Stormwater runoff is also important to manage as it flows into the Sammamish River, Lake Washington, and the Puget Sound. Trees and urban forests contribute positively to all of these goals; enhancing the urban environment, providing clean air and wildlife habitats, and mitigating stormwater runoff.

As the population of Bothell grows and development pressures continue well into the future, it is important to identify the natural resources that exist today so that policies can be established to protect these valuable Figure 1: Bothell Location Map assets. Urban canopy studies provide a top down view of the urban forest (Source: Esri Basemap) and quantify this resource at various geographic scales in addition to identifying potential planting opportunities for future canopy growth. The King Conservation District and the City of Bothell are being proactive in their efforts to preserve Bothell’s natural resources by conducting this assessment. The primary objective of this Urban Tree Canopy Assessment in the City of Bothell, WA is to map the current extent of Bothell’s urban tree canopy to raise awareness of its value and promote its protection.

45%

21%

32%

Average Citywide Tree Canopy Cover

Vegetated Possible Planting Area

Impervious, including buildings and roads

Urban Tree Canopy in Bothell Results of this study show that of Bothell’s 8,741 total acres, 45 percent was covered by tree canopy (with 3,926 acres), 22 percent was grass and open space (with 1,936 acres), and 32 percent was impervious (with 2,765 acres). Of the grass and open space, 1,831 acres have been identified as land that provides opportunity for addition tree canopy. This Possible Planting Area (PPA Vegetation) makes up 21 percent of the City. Dividing the impervious surfaces into more detailed classifications shows that nine percent of the City is covered by buildings and nine percent is covered by roads, leaving 13 percent classified as “Other Impervious”, including parking lots and sidewalks that may offer opportunities for new trees and additional canopy cover.

BOTHELL, WA URBAN CANOPY: EXECUTIVE SUMMARY

1

Assessment Boundaries and Analysis Results This study assessed Urban Tree Canopy (UTC) and Possible Planting Areas (PPA) at multiple geographic scales in order to provide actionable information to multiple audiences. By identifying what resources and opportunities exist at these scales, the King Conservation District and the City can be more proactive in their approach to protect (or expand) the urban tree canopy. Metrics were generated at the following geographies: the citywide boundary, planning subareas, land use, surface water management areas, surface water subbasins, riparian areas, parcels and Right-of-Way. Results show that the Fitzgerald / 35th SE Planning Subarea currently boasts the greatest percentage of UTC with 60 percent. The Waynita / Simonds / Norway Hill follows with 54 percent relative UTC, and as the largest Planning Subarea, it also has the greatest amount of total canopy with 804 acres, making up 20 percent of the entire city’s UTC. The Little Bear Creek and Parr Creek Surface Water Management Areas have the least amount of UTC with 27 percent and 36 percent, respectively. While the Little Swamp Creek SWMA has the most relative UTC at 65 percent, it is the smallest physical area and yields the least amount of acreage of UTC, with only 21 total acres and comprising only one percent of the City’s entire urban tree canopy.

Aside from two subbasins with extensive agriculture, the Little Bear Creek, Northeast Sammamish, and Park n’ Ride Basins have the lowest amounts of relative UTC with 27 percent, 29 percent, and 30 percent UTC, respectively. Despite the low amounts of UTC, these areas offer only moderate amounts of planting opportunity due to high percentages of impervious surfaces. These surfaces, which include areas like roads and buildings, additionally increase stormwater runoff and the need for effective surface water management.

In all riparian corridors except for three, UTC is above 50 percent. The three under 50 percent include Middle Creek, the Sammamish River, and Horse Creek. Both the Juanita West Creek and the Southwest Sammamish riparian areas contain 100 percent UTC. The total ROW land area in Bothell is 1,325 acres, of which 317 contain UTC, or 24 percent of the ROW. This ROW urban tree canopy makes up eight percent of the City’s total UTC, while the UTC within parcel boundaries make up the remaining 92 percent. More specifically, 51 percent of the City’s total tree canopy is found on single- and multi-family residential land uses, with 12 percent found on private open space and 16 percent on vacant, undeveloped lands. While city-owned open space and other government park/open space average 86 and 81 percent tree canopy cover respectively, this makes up just 9 percent of citywide total UTC.

Recommendations While there are no official adopted plans that promote the urban tree canopy, it is clear that the City values its natural resources and wants to maintain a healthy and sustainable urban environment. Therefore, it is recommended that the City utilize these assessment results to preserve and promote healthy urban tree canopy, develop an urban forest management plan that provides a shared vision and relate urban forestry efforts to greater citywide initiatives/priorities. These recommendations are a starting point for an interdisciplinary goal-setting process and determination of priorities and strategies.

BOTHELL, WA URBAN CANOPY: EXECUTIVE SUMMARY

2

PROJECT FUNDAMENTALS & METHODOLOGY This section describes the methods through which land cover, urban tree canopy, and possible planting areas were mapped. This is fundamental, as these datasets are the basis for the metrics reported at the selected target geographies.

Mapping Land Cover The most fundamental component of this urban tree canopy assessment is the creation of an initial land cover data set. The process began with the acquisition of 2015 high-resolution (1-meter) aerial imagery from the USDA’s National Agricultural Imagery Program (NAIP). An object-based image analysis (OBIA) software program called Feature Analyst (ArcGIS Desktop) was used to classify features through an iterative approach, where objects’ spectral signatures across four bands (blue, green, red, and near-infrared), textures, and pattern relationships were taken into account. This process resulted in five initial land cover classes as shown in Figure 2.

After manual classification improvement and quality control, additional data layers from the city, (such as buildings, roads, and other impervious surfaces) were utilized to capture finer feature detail and further categorize the land cover dataset.

Urban Tree Canopy

Non-Canopy Vegetation

Impervious Surfaces

Bare Soil

Water Bodies

Tree cover when viewed and mapped from above

Grass and open space vegetation

Hard surfaces where rainfall cannot permeate

Not included in possible planting areas

Bodies of water removed from total land cover

Figure 2: Five Primary Land Cover Classes generated from Aerial Imagery-based Analysis

Identifying Possible Planting and Unsuitable Areas Once the land cover dataset was finalized and the existing Urban Tree Canopy was established, Possible Planting Areas for both vegetation and impervious surfaces were then derived from the Non-Canopy Vegetation and Impervious land cover classes. “Unsuitable” areas were incorporated into the data set to identify where it is not feasible to plant trees. The City of Bothell provided GIS data delineating these unsuitable areas, which included sports fields, utility easments, and Pioneer Cemetery (as shown in Figure 3). Roads and buildings, also provided by the City, were isolated from the impervious surfaces and identified as “unsuitable impervious”. Thus, the final results are reported with vegetated possible planting areas (PPA-Veg), impervious possible planting areas (PPAIA), total possible planting areas (To-PPA), unsuitable impervious (roads and buildings), other unsuitable (sports fields, etc), and total unsuitable.

BOTHELL, WA URBAN CANOPY: PROJECT FUNDAMENTALS & METHODOLOGY

3

Figure 3: Sports Fields, Utility Easements, and Pioneer Cemetery, are considered unsuitable for planting

Visualizing Urban Tree Canopy Results Maps showing urban tree canopy (UTC) in this report express relative levels of canopy as a percentage of land area (not including water). UTC levels are divided into meaningful categories for each of the assessment area boundaries and may vary slightly depending on the distribution within the target geographies. For Parcels, UTC levels are broken up into four classes: 20 percent or Less UTC, 21-40 percent UTC, 41-70 percent UTC, and Greater than 70 percent UTC. Figure 4 provides visual examples of what the varying levels of UTC look like against the aerial imagery, all shown at the same scale of 1:2,400.

14% UTC (low)

27% UTC

56% UTC

82% UTC (High)

Figure 4: Examples of Relative Canopy Coverage by Parcel

BOTHELL, WA URBAN CANOPY: PROJECT FUNDAMENTALS & METHODOLOGY

4

Defining Assessment Levels In order to better inform various stakeholders (city officials, city staff, and citizens alike), urban tree canopy and associated information was calculated for a variety of geographic boundaries. These include the citywide boundary, planning subareas, land use, surface water management areas, surface water subbasins, riparian areas, parcels and Right-of-Way. Outputs include total area (in acres or square feet) and relative values (as percentages) for urban tree canopy (UTC), possible planting areas (PPA), impervious surfaces, and unsuitable areas. Assessment levels include the following geographic boundaries: The City of Bothell municipal boundary is the one (1) main overarching area of interest for which all metrics are summarized.

Thirteen (13) Planning Subareas were evaluated to identify the amount of tree canopy as it relates to the Planning Department, and to help inform planning management (Figure 7).

The Cityâ&#x20AC;&#x2122;s Land Use Classes were created and analyzed to represent current human uses and land characteristics, totaling 10 classifications.

Twelve (12) Surface Water Management Areas (SWMA) were analyzed to evaluate where UTC is lacking and where it could be expanded to assist in stormwater management efforts.

Metrics for Surface Water Subbasins show the various levels of canopy and possible planting area within each watershed. Given treesâ&#x20AC;&#x2122; potential to mitigate stormwater runoff by intercepting precipitation, it is helpful to know which areas are lacking in UTC and have opportunities to grow additional tree canopy.

Riparian Areas were identified by buffering 34 streams by 100 feet, capturing their surrounding areas, including plant habitats and communities along river margins and banks.

Citywide Right-of-Way (ROW) covers the area where parcels are lacking, including street ROW and the river corridor. Generally, this is land that is managed by the City and the UTC results can inform City tree planting and management efforts (Figure 6).

Parcels are the finest level of detail for which metrics were generated. UTC and PPA is reported for over 12,000 individual properties, including residential and commercial (Figure 5).

Figure 5: Parcel Level Target Geography (scale = 1:8,000)

Figure 6: Rights-of-Way are the inverse of parcels (scale = 1: 8,000)

BOTHELL, WA URBAN CANOPY: PROJECT FUNDAMENTALS & METHODOLOGY

Figure 7: Planning Subareas within the Bothell City Limit (scale = 1:196,000)

5

ASSESSMENT RESULTS & KEY FINDINGS This section presents the key findings of this study, including the land cover base map as well as the canopy analysis results, which were analyzed across various geographic assessment boundaries. These results, or metrics, help inform a strategic approach to identifying future planting areas. Complete assessment results for target geographies and additional maps can be found in the Appendix.

Citywide Land Cover In 2015, 45 percent of Bothell was covered by tree canopy, 22 percent was grass and open space, and 32 percent was impervious. Further dividing the impervious surface areas into more detailed classifications shows that nine percent of the City is covered by buildings and nine percent is covered by roads, leaving 13 percent classified as “Other Impervious”. This remaining 13 percent includes parking lots and sidewalks, which may offer opportunities for new tree plantings and additional canopy cover. Table 1 shows the generalized land cover results, while Figure 8 shows the more detailed map and distribution.

Table 1: Generalized Land Cover Classification Results

Total Acres

Tree Canopy (acres)

Tree Canopy %

Grass / Open Space (acres)

Grass / Open Space %

Impervious (acres)

Impervious %

Water (acres)

Water %

Soil / Dry Vegetation (acres)

Soil / Dry Vegetation %

8,741

3,926

45%

1,936

22%

2,765

32%

65

0.7%

49

0.6%

Citywide Urban Tree Canopy This urban tree canopy assessment utilized the land cover map as a foundation to determine Possible Planting Areas (PPA) throughout the City. Additional layers and information regarding land considered unsuitable for planting was also analyzed. It should be noted that the results of this study are based off of land area, not total area (note the difference between Total Acres in Table 1 and Land Area in Table 2). Results show that within the City of Bothell, WA, 3,926 acres are cover by urban tree canopy (UTC), making up 45 percent of the 8,676 land acres, and 1,831 acres of land has been identified as non-canopy vegetation that provides the possibility for addition tree canopy. This Possible Planting Area (PPA Vegetation) makes up 21 percent of the City. Nonbuilding and non-road impervious areas cover 1,158 acres that may also offer additional planting opportunity (PPA Impervious), while 20 percent of the City’s land has been identified as unsuitable for planting. This includes sport fields, golf course fairways, buildings and roads, and soil/dry vegetation.

Table 2: Urban Tree Canopy Assessment Results *Land Area (acres)

UTC (acres)

UTC %

PPA Vegetation (acres)

PPA Vegetation %

PPA Impervious (acres)

PPA Impervious %

Total Possible Planting (acres)

Total Possible Planting %

Unsuitable UTC* (acres)

Unsuitable UTC* %

8,676

3,926

45%

1,831

21%

1,158

13%

2,989

34%

1,761

20%

*Note: Percentages are based on Land Area

CITY OF BOTHELL, WA ASSESSMENT RESULTS & KEY FINDINGS

6

Land Cover in Bothell, WA

Figure 8: Detailed Land Cover Classifications and Distribution

CITY OF BOTHELL, WA ASSESSMENT RESULTS & KEY FINDINGS

7

Planning Subareas This study assessed urban tree canopy (UTC) totals and Possible Planting Areas (Vegetation, Impervious, and Total PPA) for 13 Planning Subareas. The Fitzgerald / 35th SE Planning Subarea currently boasts the greatest percentage of UTC with 60 percent canopy coverage. The Waynita / Simonds / Norway Hill Subarea follows with 54 percent relative UTC, but as the largest Planning Subarea, it also has the greatest amount of total canopy with 804 acres. This large Planning Subarea contains 20 percent of the entire cityâ&#x20AC;&#x2122;s UTC. Table 3: Top 3 Planning Subareas for Percent of Urban Tree Canopy

Planning Subarea

Land Area (acres)

UTC (acres)

UTC %

PPA Veg (acres)

PPA Veg %

PPA IA (acres)

PPA IA %

Total PPA (acres)

Total PPA %

Fitzgerald / 35th SE

445

268

60%

94

21%

30

7%

124

28%

Waynita / Simonds / Norway Hill

1,478

804

54%

286

19%

132

9%

418

28%

Country Village / Lake Pleasant / Bothell-Everett Hwy

285

151

53%

50

18%

40

14%

90

31%

In terms of possible planting area and opportunities to expand the urban tree canopy, Westhill has the greatest relative amount of PPA Vegetation with 20 percent (206 acres), while Waynita / Simonds / Norway Hill offers the most actual area with 286 acres of PPA Veg.

Figure 9: Percent of Urban Tree Canopy and Vegetated Possible Planting Area by Planning Subarea

CITY OF BOTHELL, WA ASSESSMENT RESULTS & KEY FINDINGS

8

Land Use This study processed urban tree canopy (UTC) totals and Possible Planting Areas (Vegetation, Impervious, and Total PPA) data for Bothell land use classes. Ten generalized land use classes were created to reflect current human use and land cover information as they relate to UTC. City-owned Open Space and Other Governmentowned Park/Open Space land use have the highest canopy cover at 86 percent and 81 percent, respectively.

However, these two classes make up a combined 9 percent of all canopy citywide, while Single Family Land Use properties average 45 percent canopy cover, accounting for 44 percent of all canopy in the study area.

The greatest opportunities to expand the urban tree canopy are within Single Family and Private Open Space land use classifications. Both classifications contain 27 percent PPA Vegetation. Government/Public Facility (26 percent) and City-owned Park (19 percent) classes also present significant opportunity for canopy growth, most of which is city-owned and managed.

Vacant-Undeveloped land use contributes 16 percent of total city-wide urban tree canopy and a significantly high overall UTC of 70 percent. This classification, it should be noted, will diminish in size with future development as land use within this classification changes. Opportunities to preserve existing UTC within this classification should be considered as this land is absorbed into other land use categories as a result of future development.

See maps in the Appendix of UTC and PPA by land use.

Percent of UTC and PPA (V) by Land Use Class 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0%

86%

81% 70%

69%

40% 27% 19% 13%

50%

45% 32%

29%

26% 15%

14%

27%

25% 13%

17%

17%

Urban Tree Canopy (%) Possible Planting Area (Veg) (%)

Figure 10: UTC and PPA by Land Use

CITY OF BOTHELL, WA ASSESSMENT RESULTS & KEY FINDINGS

9

Surface Water Management Areas This study processed urban tree canopy (UTC) totals and Possible Planting Areas (Vegetation, Impervious, and Total PPA) data for 12 Surface Water Management Areas (SWMA). The Little Bear Creek SWMA and Parr Creek SWMAs have the least amount of UTC with 27 percent and 36 percent, respectively. While the Little Swamp Creek SWMA has the most relative UTC at 65 percent, it is the smallest physical area and yields the least amount of acreage of UTC, with only 21 total acres (comprising only one percent of the Cityâ&#x20AC;&#x2122;s entire urban tree canopy).

It should also be noted that the Little Bear Creek and Parr Creek SWMAs also have the greatest percentages of impervious surface areas, with Little Bear at 48 percent impervious and Parr Creek at 40 percent impervious. Of these impervious surfaces, 21 acres in Little Bear and 170 acres in Parr Creek may be suitable for new canopy, meaning they are not buildings or roads.

Considering the benefits of tree canopy in helping manage stormwater runoff, this may be a good approach to locating areas to consider adding tree canopy.

Figure 11: Percent Urban Tree Canopy by Surface Water Management Area

Figure 12: Percent Impervious Surface Area by Surface Water Management Area CITY OF BOTHELL, WA ASSESSMENT RESULTS & KEY FINDINGS

10

Surface Water Subbasins This study processed urban tree canopy (UTC) totals, and Possible Planting Area (PPA) data for 36 Surface Water Subbasins that intersect Bothell, as delineated and provided by the City. Findings at a watershed level can be used for any number of different studies and projects, including hydrologic modeling tools, water resource management plans, forest management plans, water quality studies, and more.

Figure 13: Highway Interchanges, Dense Housing Developments, and Agricultural Lands Contribute to areas of Low Urban Tree Canopy

Two subbasins with the lowest relative amounts of UTC, Swamp Creek South and Little Swamp Creek South, located on the western edge of the City, appear to have low UTC due to agricultural activity. These subbasins also have a high percentage of vegetated possible planting area (PPA-Veg), which is the result of open fields being used for agriculture. While agricultural land was not removed from the unsuitable areas identified in the study, these areas may not actually offer opportunity for additional tree canopy if they are being actively farmed. Aside from those two subbasins*, the Little Bear Creek, Northeast Sammamish, and Park nâ&#x20AC;&#x2122; Ride Basin have the lowest amounts of relative UTC, with 27 percent, 29 percent, and 30 percent UTC, respectively. Despite the low amounts of UTC, these areas only offer moderate amounts of planting opportunity since they contain some of the highest percentages of impervious surfaces, such as roads and buildings, increasing stormwater runoff and the need for surface water management. These results are shown in Table 4. For complete results, refer to the Appendix section of this report.

Table 4: Lowest 3 Surface Water Subbasins for Percent of Urban Tree Canopy (*after those containing agricultural land) Land Area (acres)

UTC (acres)

UTC %

PPA Veg (acres)

PPA Veg %

PPA Impervious (acres)

PPA Impervious %

Total Impervious (acres)

Total Impervious %

Little Bear Creek

127

34

27%

27

22%

21

16%

61

48%

Northeast Sammamish

133

38

29%

34

26%

17

13%

57

43%

Park'n Ride Basin

161

49

30%

40

25%

29

18%

69

43%

Surface Water Subbasin

CITY OF BOTHELL, WA ASSESSMENT RESULTS & KEY FINDINGS

11

Riparian Areas This study processed urban tree canopy (UTC) totals and Possible Planting Areas (Vegetation, Impervious, and Total PPA) data for all riparian areas within Bothell. Riparian areas are part of river and stream corridors, including plant habitats and communities along river margins and banks. For this study, riparian areas were identified by buffering all stream centerlines by 100 feet. UTC is above 50 percent in all riparian corridors, except for 3. These bottom 3 are identified in Table 5 and include those areas surrounding Middle Creek, the Sammamish River, and Horse Creek. Both the Juanita West Creek and the Southwest Sammamish riparian areas contain 100 percent UTC. Table 5: Lowest 3 Riparian Areas for Percent of Urban Tree Canopy Land Area (acres)

UTC (acres)

% UTC

PPA Vegetation (acres)

% PPA Vegetation

PPA Impervious (acres)

PPA Impervious %

Middle Creek

27

11

40%

7

25%

4

16%

Sammamish River

48

21

45%

19

39%

4

8%

Horse Creek

78

37

48%

10

13%

15

19%

Riparian Area

Right-of-Way Citywide Urban Tree Canopy (UTC) totals and Possible Planting Areas (Vegetation, Impervious, and Total PPA) have been evaluated for citywide Right-of-Way (ROW). The total ROW land area in Bothell (excluding water) is 1,325 acres, of which 317 contain UTC, or 24 percent of the ROW. This urban tree canopy makes up 8 percent of the Cityâ&#x20AC;&#x2122;s total UTC, while the UTC within parcel boundaries make up the remaining 92 percent.

Within the ROW, an additional 216 acres of vegetated possible planting area still remains, and 131 acres of Figure 14: Trees within the Right-of-Way near the Cityâ&#x20AC;&#x2122;s Municipal Court possible planting area within impervious surfaces.

(Source: Bing Maps) This includes sidewalk areas where planting pits can be established, similar to the planting pits along the south side of NE 183rd Street as shown in Figure 15.

Because ROW is owned and managed by the City, possible planting areas located within them are easy targets for increasing tree canopy cover.

Table 6: Assessment Results by Citywide Right-of-Way Citywide Land Area (acres)

ROW Area Land (acres)

UTC (acres)

UTC in ROW %

Citywide Distribution of ROW UTC %

PPA Veg (acres)

% PPA Veg

PPA Impervious (acres)

% PPA Impervious

Total Possible Planting (acres)

Total Possible Planting %

1,330

1,325

317

24%

8%

216

16%

131

10%

347

26%

CITY OF BOTHELL, WA ASSESSMENT RESULTS & KEY FINDINGS

12

Parcels The most detailed assessment geography analyzed for this study was the parcel layer. This study calculated urban tree canopy (UTC) totals and Possible Planting Areas (Vegetation, Impervious, and Total PPA) for each individual property with over 12,000 records. Due to the size of the dataset, comprehensive data have been provided to the City in GIS format, and are not included in tabular format in this report.

Figure 15: Percent Urban Tree Canopy by Parcel

CITY OF BOTHELL, WA ASSESSMENT RESULTS & KEY FINDINGS

13

RECOMMENDATIONS While there are no official adopted plans that promote efforts to grow the urban tree canopy and Bothell lacks an established urban forestry program, it is clear that the City values its natural resources and wants to maintain a healthy and sustainable urban environment. As such, the City should use these suggestions, along with the key findings in this report, as a starting point for an interdisciplinary goal-setting process and determination of priorities and strategies.

Recommendation 1: Utilize assessment results to preserve and promote urban tree canopy.

This assessment report provides detailed information about current UTC and possible planting areas, both citywide and at various geographic scales. These results should be utilized to enhance and promote forest preservation and management efforts, including the establishment of a baseline urban tree canopy cover percentage. The King Conservation District and the City of Bothell should disseminate the data from this study to diverse partners for urban forestry and other applications while they are current and most useful for decisionmaking and implementation planning.

Recommendation 2: Develop an urban forest management plan to provide a shared vision.

These assessment results should be used to encourage investment in forest monitoring, maintenance, management, and in preparing supportive information for local budget requests/grant applications. The information from this study can help establish canopy cover goals for the short and long term. In addition, it is recommended that the City hire an arborist, city forester, or urban forester to increase inspection, maintenance, and enforcement. Having a professional ISA certified arborist on staff is one first step in identifying and addressing forest management needs.

Recommendation 3: Relate urban forestry efforts to greater citywide initiatives and priorities.

The City of Bothellâ&#x20AC;&#x2122;s urban forest green infrastructure is providing a great deal of benefits to the City that can be quantified. These benefits often relate back to greater community concerns and citywide initiatives and priorities. For example, air and water quality, stormwater management, and energy savings and all benefits that come from the urban forest. The City should use the USDAâ&#x20AC;&#x2122;s i-Tree suite of software, along with the results of this study, to measure the value of its current urban tree canopy.

BOTHELL, WA URBAN CANOPY: RECOMMENDATIONS

14

APPENDIX Accuracy Assessment Classification accuracy serves two main purposes: First, accuracy assessments provide information to technicians producing the classification about where processes need to be improved and where they are effective. Secondly, measures of accuracy provide information about how to use the classification and how well land cover classes are expected to estimate actual land cover on the ground. Even with high resolution imagery, very small differences in classification methodology and image quality can have a large impact on overall map area estimations. The classification accuracy error matrix illustrated in Figure 16 contains confidence intervals that report the high and low values that could be expected for any comparison between the classification data and what actual, on the ground land cover was in 2015. This accuracy assessment was completed using high resolution aerial imagery, with computer and manual verification. No field verification was completed.

The internal accuracy assessment was completed in five (5) steps 1. Approximately one thousand (1,000) sample points were randomly distributed across the study area and assigned a random numeric value.

2. Each sample point was then referenced using the NAIP imagery and assigned one of the five land cover classes (“Ref_ID”) mentioned above.

3. In the event that the reference value could not be discerned from the imagery, the point was dropped from the accuracy analysis. In this case, no points were dropped.

4. An automated script was then used to assign values from the classification raster to each point (“Eval_ID”). The classification supervisor provides unbiased feedback to quality control technicians regarding the types of corrections required. Misclassified points (where reference ID does not equal evaluation ID) and corresponding land cover are inspected for necessary corrections to the land cover1.

Accuracy is re-evaluated (repeat steps 3 & 4) until an acceptable classification accuracy is achieved.

Sample Error Matrix Interpretation Statistical relationships between the reference pixels (representing the true conditions on the ground) and the intersecting classified pixels are used to understand how closely the entire classified map represents the Bothell, WA landscape. The error matrix shown in Figure 16 represents the intersection of reference pixels manually identified by a human observer (columns) and classification category of pixels in the classified image (rows). The gray boxes along the diagonals of the matrix represent agreement between the two pixel maps. Off-diagonal values represent the number pixels manually referenced to the column class that were classified as another category in the classification image. Overall accuracy is computed by dividing the total number of correct pixels by the total number of pixels reported in the matrix (422 + 178 + 270 + 2 + 9 = 881 / 1,000 = 88 percent), and the matrix can be used to calculate per class accuracy percent’s. For example, 422 points were manually identified in the reference map as Tree Canopy, and 467 of those pixels were classified as Tree Canopy in the classification 1

Note that by correcting locations associated with accuracy points, bias is introduced to the error matrix results. This means that matrix results based on a new set of randomly collected accuracy points may result in significantly different accuracy values.

BOTHELL, WA URBAN CANOPY: APPENDIX

15

map. This relationship is called the “Producer’s Accuracy” and is calculated by dividing the agreement pixel total (diagonal) by the reference pixel total (column total). Therefore, the Producer’s Accuracy for Tree Canopy is calculated as: (422/467 = .90), meaning that we can expect that ~90 percent of all tree canopy in the Bothell, WA study area were classified as Tree Canopy in the classification map.

Figure 16: Error Matrix for Land Cover Classifications within Bothell, WA

Conversely, the “User’s Accuracy” is calculated by dividing the number agreement pixel total by the total number of classified pixels in the row category. For example, 422 classification pixels intersecting reference pixels were classified as Tree Canopy, but 21 pixels were identified as Vegetation and 9 pixels were identified as Impervious in the reference map. Therefore, the User’s Accuracy for Tree Canopy is calculated as: (422/452 = 0.93), meaning that ~93 percent of the pixels classified as Tree Canopy in the classification were actual tree canopy. It is important to recognize the Producer’s and User’s accuracy percent values are based on a sample of the true ground cover, represented by the reference pixels at each sample point. Interpretation of the sample error matrix results indicates this land cover, and more importantly, tree canopy, were accurately mapped in Bothell, WA. The largest sources of classification confusion exist between tree canopy and vegetation, and vegetation and impervious.

Results Interpretation of the sample error matrix results indicates this land cover (and more importantly, tree canopy) was accurately mapped in Bothell, WA. The largest sources of classification confusion exist between tree canopy and vegetation, and vegetation and impervious.

BOTHELL, WA URBAN CANOPY: APPENDIX

16

Comprehensive Assessment Area Results This Urban Tree Canopy (UTC) Assessment of Bothell, WA was conducted by Plan-It Geo, LLC for King Conservation District and the City of Bothell. The assessment summarized metrics for a variety of target geographies. Metrics were calculated in acres and percent for Urban Tree Canopy (UTC), Possible Planting Area Vegetation (PPA Vegetation), Possible Planting Area Impervious (PPA Impervious), Total Possible Planting Area (Total PPA), and Areas Unsuitable for Planting (Unsuitable). This section provides results for each target geography, as well as maps showing the distribution of the results.

Analysis results and additional maps are provided as follows: 1.

2.

3.

4.

5.

6.

Planning Subareas Land Use Surface Water Management Areas Surface Water Subbasins Riparian Areas Parcels

BOTHELL, WA URBAN CANOPY: APPENDIX

17

City of Bothell, WA Geographic Summary: Planning Subareas This table summarizes UTC metrics for Bothell, WA Planning Subareas in Acres and percent including Urban Tree Canopy (UTC), Possible Planting Area Vegetation (PPA Vegetation), Possible Planting Area Impervious (PPA Impervious), Total Possible Planting Area (Total PPA), and Areas Unsuitable for Planting (Unsuitable) Table 7: Planning Subarea Assessment Results

Planning Subarea Bloomberg Hill Brickyard Road / Queensgate Canyon Creek / 39th SE

Total Land Acres

UTC Acres

UTC %

Dist. of UTC %

PPA (Veg.) Acres

PPA (Veg.) %

PPA (Imp.) Acres

PPA (Imp.) %

Total PPA Acres

Total PPA %

Unsuit able UTC (acres)

Unsuit able UTC %

297

84

28%

2%

69

23%

42

14%

111

37%

102

34%

459

176

38%

4%

88

19%

59

13%

148

32%

135

30%

356

176

49%

4%

63

18%

51

14%

114

32%

66

19%

1,004

436

43%

11%

176

17%

205

20%

380

38%

187

19%

Country Village / Lake Pleasant / Bothell-Everett Hwy

285

151

53%

4%

50

18%

40

14%

90

31%

44

15%

Downtown

510

201

39%

5%

85

17%

107

21%

193

38%

116

23%

Fitzgerald / 35th SE

445

268

60%

7%

94

21%

30

7%

124

28%

53

12%

Maywood / Beckstrom Hill

896

346

39%

9%

223

25%

110

12%

333

37%

218

24%

North Creek / 195th

879

363

41%

9%

151

17%

170

19%

321

36%

196

22%

798

356

45%

9%

194

24%

81

10%

275

35%

167

21%

569

287

50%

7%

146

26%

52

9%

198

35%

84

15%

1,478

804

54%

20%

286

19%

132

9%

418

28%

256

17%

698

277

40%

7%

206

30%

79

11%

285

41%

136

19%

8,673

3,925

45%

100%

1,831

21%

1,158

13%

2,989

34%

1,760

20%

Canyon Park

Queensborough / Brentwood / Crystal Springs Shelton View / Meridian / 3rd SE Waynita / Simonds / Norway Hill Westhill

Total

BOTHELL, WA URBAN CANOPY: APPENDIX

18

City of Bothell, WA Geographic Summary: Planning Subareas

Figure 17: Percent Urban Tree Canopy by Planning Subarea

BOTHELL, WA URBAN CANOPY: APPENDIX

19

City of Bothell, WA Geographic Summary: Planning Subareas

Figure 18: Percent Possible Planting Area (Vegetation) by Planning Subarea

BOTHELL, WA URBAN CANOPY: APPENDIX

20

City of Bothell, WA Geographic Summary: Land Use This table summarizes UTC metrics for Bothell, WA Land Use Classifications in Acres and percent including Urban Tree Canopy (UTC), Possible Planting Area Vegetation (PPA Vegetation), Possible Planting Area Impervious (PPA Impervious), Total Possible Planting Area (Total PPA), and Areas Unsuitable for Planting (Unsuitable).

Table 8: Land Use Assessment Results Total Area (Acres)

Land Area (Acres)

UTC (Acres)

UTC %

Distribution of UTC %

City-owned Open Space

194

194

167

86%

4.6%

City-owned Park

69

68

27

40%

0.7%

Other Government-owned Park/Open Space

227

207

167

81%

4.6%

Private Open Space

625

610

420

69%

11.6%

1,036

1,033

299

29%

8.3%

122

122

39

32%

1.1%

Single Family

3,494

3,478

1,579

45%

43.7%

Multi Family

513

511

258

50%

7.1%

School

296

296

73

25%

2.0%

Vacant - Undeveloped

836

833

580

70%

16%

7,411

7,351

3,609

49%

100%

Land Use

Commercial / Church Government / Public Facility

Totals

PPA Veg (Acres)

PPA Veg %

PPA Impervious (Acres)

PPA Impervious %

To PPA (Acres)

To PPA %

City-owned Open Space

24

13%

2

1%

26

13%

0

0%

City-owned Park Other Government-owned Park/Open Space

13

19%

6

9%

19

29%

22

32%

29

14%

7

3%

36

17%

4

2%

Private Open Space

166

27%

11

2%

176

29%

14

2%

Commercial / Church

156

15%

372

36%

527

51%

206

20%

Government / Public Facility

32

26%

31

25%

63

52%

20

16%

Single Family

943

27%

378

11%

1,321

38%

579

17%

Multi Family

65

13%

77

15%

142

28%

111

22%

School

49

17%

99

33%

148

50%

74

25%

Vacant - Undeveloped

139

17%

44

5%

183

22%

70

8%

1,616

22%

1,027

14%

2,642

36%

1,100

15%

Land Use

Totals

BOTHELL, WA URBAN CANOPY: APPENDIX

Total Unsuitable UTC

Total Unsuitable UTC %

21

City of Bothell, WA Geographic Summary: Land Use

Figure 19: Land Use Categories

BOTHELL, WA URBAN CANOPY: APPENDIX

22

City of Bothell, WA Geographic Summary: Land Use

Figure 20: Percent Urban Tree Canopy by Land Use BOTHELL, WA URBAN CANOPY: APPENDIX

23

City of Bothell, WA Geographic Summary: Land Use

Figure 21: Percent Possible Planting Area (Vegetation) by Land Use

BOTHELL, WA URBAN CANOPY: APPENDIX

24

City of Bothell, WA Geographic Summary: Surface Water Management Areas This table summarizes UTC metrics for Bothell, WA Surface Water Management Areas in Acres and percent including Urban Tree Canopy (UTC), Possible Planting Area Vegetation (PPA Vegetation), Possible Planting Area Impervious (PPA Impervious), Total Possible Planting Area (Total PPA), and Areas Unsuitable for Planting (Unsuitable).

Table 9: Surface Water Management Area Assessment Results Total Land Acres

UTC Acres

UTC %

Dist. of UTC %

PPA (Veg.) Acres

PPA (Veg.) %

PPA (Imp.) Acres

PPA (Imp.) %

Total PPA Acres

Total PPA %

Unsuit able UTC (acres)

Unsuit able UTC %

Boy Scout Creek

505

255

50%

6%

103

20%

49

10%

152

30%

99

20%

Canyon Park

798

347

43%

9%

140

18%

166

21%

306

38%

145

18%

SWMA

Fitzgerald

435

259

59%

7%

95

22%

33

7%

128

29%

49

11%

1,586

649

41%

17%

339

21%

248

16%

588

37%

349

22%

Juanita

437

205

47%

5%

80

18%

48

11%

128

29%

104

24%

Little Bear Creek Little Swamp Creek Little Swamp Creek Parr Creek

127

34

27%

1%

27

22%

21

16%

48

38%

45

35%

884

377

43%

10%

271

31%

88

10%

359

41%

148

17%

33

21

65%

1%

5

15%

2

5%

7

20%

5

15%

889

320

36%

8%

171

19%

170

19%

341

38%

227

26%

Queensborough

1,543

678

44%

17%

340

22%

196

13%

537

35%

328

21%

787

414

53%

11%

133

17%

80

10%

213

27%

160

20%

651

367

56%

9%

126

19%

57

9%

183

28%

101

16%

8,675

3,926

45%

100%

1,831

21%

1,158

13%

2,989

34%

1,761

20%

Horse Creek

Riverside Waynita Total

BOTHELL, WA URBAN CANOPY: APPENDIX

25

City of Bothell, WA Geographic Summary: Surface Water Management Areas

Figure 22: Percent Urban Tree Canopy by Surface Water Management Area

BOTHELL, WA URBAN CANOPY: APPENDIX

26

City of Bothell, WA Geographic Summary: Surface Water Management Areas

Figure 23: Percent Possible Planting Area (Vegetation) by Surface Water Management Area

BOTHELL, WA URBAN CANOPY: APPENDIX

27

City of Bothell, WA Geographic Summary: Surface Water Subbasins This table summarizes UTC metrics for Bothell, WA Surface Water Subbasins in Acres and percent including Urban Tree Canopy (UTC), Possible Planting Area Vegetation (PPA Vegetation), Possible Planting Area Impervious (PPA Impervious), Total Possible Planting Area (Total PPA), and Areas Unsuitable for Planting (Unsuitable).

Table 10: Surface Water Subbasin Assessment Results Total Land Acres

UTC Acres

UTC %

Dist. of UTC %

Total PPA Acres

Total PPA %

Unsuita ble UTC (acres)

Blyth Creek

21

19

89%

0.5%

2

8%

1

Boy Scout Creek

106

55

52%

1%

17

16%

11

3%

2

10%

0.2

1%

11%

28

26%

23

22%

Brickyard Creek

164

62

38%

2%

31

19%

23

14%

54

33%

48

29%

Cougar Creek

258

91

35%

2%

60

23%

Crystal Creek

232

128

55%

3%

46

20%

48

19%

108

42%

58

23%

22

9%

68

29%

36

16%

E. Riverside Creek

136

57

42%

1%

18

Filbert Creek

31

12

39%

0.3%

8

13%

16

12%

34

25%

45

33%

26%

3

11%

12

38%

7

24%

Horse Creek

735

326

44%

8%

143

19%

115

16%

258

35%

150

20%

Juanita Creek

477

218

46%

Juanita West

4

4

95%

6%

89

19%

54

11%

143

30%

116

24%

0.1%

0.2

4%

0.0

1%

0.2

5%

0.0

0%

Junco Creek

134

57

42%

Little Bear Creek

127

34

27%

1%

24

18%

31

23%

55

41%

22

17%

1%

27

22%

21

16%

48

38%

45

35%

Little Swamp Creek

396

178

45%

5%

115

29%

40

10%

155

39%

64

16%

Little Swamp Creek S.

122

Little Swamp Northwest

88

27

22%

1%

55

45%

14

12%

69

56%

26

21%

39

45%

1%

26

30%

7

9%

33

38%

15

17%

Maltby Hill Creek

303

181

60%

5%

40

13%

36

12%

76

25%

46

15%

Middle Creek

263

85

32%

2%

51

19%

70

27%

121

46%

57

22%

North Creek

969

472

49%

12%

205

21%

128

13%

333

34%

164

17%

Northeast Sammamish

133

38

29%

1%

34

26%

17

13%

51

38%

44

33%

Northwest Sammamish

211

94

45%

2%

52

24%

23

11%

74

35%

42

20%

Palm Creek

102

51

50%

1%

22

21%

11

11%

33

32%

18

18%

Park'n Ride Basin

161

49

30%

1%

40

25%

29

18%

68

42%

44

27%

Parr Creek

726

254

35%

6%

131

18%

149

21%

280

39%

193

27%

Perry Creek

695

284

41%

7%

152

22%

99

14%

251

36%

160

23%

Queensborough Creek

383

147

38%

4%

92

24%

49

13%

141

37%

95

25%

Surface Water Subbasin

PPA (Veg.) Acres

PPA (Veg.) %

PPA (Imp.) Acres

PPA (Imp.) %

Unsuit able UTC %

Red Basin

23

7

33%

0.2%

4

17%

5

21%

9

38%

7

29%

Riverside Creek

122

79

65%

2%

22

18%

7

6%

29

24%

14

11%

Royal Anne Creek

286

159

56%

4%

65

23%

20

7%

85

30%

41

15%

Sammamish R. Norway Hill

231

152

66%

4%

35

15%

21

9%

55

24%

24

11%

Southeast Sammamish

78

34

43%

1%

18

23%

8

11%

26

33%

18

23%

Southwest Sammamish

148

99

67%

3%

34

23%

5

3%

39

26%

10

7%

Spring Stream

151

83

55%

2%

37

24%

13

9%

50

33%

18

12%

Swamp Creek

38

23

61%

1%

7

18%

2

6%

9

24%

6

15%

Swamp Creek South

37

3

9%

0.1%

27

73%

1

4%

28

77%

5

14%

Waynita Creek Woods (Cole) Creek

495 79 8,663

263 58 3,922

53% 73% 45%

7% 1% 100%

90 14 1,830

18% 18% 21%

51 3 1,153

10% 4% 13%

141 17 2,983

29% 21% 34%

90 4 1,758

18% 5% 20%

Total

BOTHELL, WA URBAN CANOPY: APPENDIX

28

City of Bothell, WA Geographic Summary: Surface Water Subbasins

Figure 24: Percent Urban Tree Canopy by Surface Water Subbasin

BOTHELL, WA URBAN CANOPY: APPENDIX

29

City of Bothell, WA Geographic Summary: Surface Water Subbasins

Figure 25: Percent Possible Planting Area (Vegetation) by Surface Water Subbasin

BOTHELL, WA URBAN CANOPY: APPENDIX

30

City of Bothell, WA Geographic Summary: Riparian Areas This table summarizes UTC metrics for Bothell, WA Riparian Areas in Acres and percent including Urban Tree Canopy (UTC), Possible Planting Area Vegetation (PPA Vegetation), Possible Planting Area Impervious (PPA Impervious), Total Possible Planting Area (Total PPA), and Areas Unsuitable for Planting (Unsuitable).

Table 11: Riparian Area Assessment Results Unsuita ble UTC (acres)

Total Land Acres

UTC Acres

UTC %

Dist. of UTC %

PPA (Veg.) Acres

PPA (Veg.) %

PPA (Imp.) Acres

PPA (Imp.) %

Total PPA Acres

Total PPA %

Boy Scout Creek

11

9

77%

1%

1

8%

0.4

3%

1

11%

1

12%

Brickyard Creek

10

5

55%

1%

1

12%

1

9%

2

21%

2

24%

Cole/Woods Creek

21

17

81%

2%

3

14%

0.4

2%

3

16%

1

3%

Cougar Creek

9

7

75%

1%

1

11%

0.5

5%

2

16%

1

8%

Crystal Creek

31

27

90%

4%

2

5%

1

2%

2

7%

1

3%

E. Riverside Creek

19

16

85%

2%

1

6%

1

3%

2

9%

1

6%

East Fork Waynita Creek

35

26

72%

3%

5

13%

1

4%

6

18%

4

10%

Riparian Area

Unsuita ble UTC %

Filbert Creek

6

5

74%

1%

0.2

3%

0.2

3%

0.4

6%

1

20%

Horse Creek

78

37

48%

5%

10

13%

15

19%

25

32%

16

20%

Juanita Creek

72

54

75%

7%

7

10%

3

4%

10

14%

8

11%

Juanita West Creek

0.5

0.5

100%

0.1%

0.0

0%

0.0

0.0%

0.0

0.0%

0.0

0.0%

Junco Creek

21

13

61%

2%

3

12%

4

16%

6

28%

2

11%

Little Swamp Creek

49

31

62%

4%

10

21%

3

6%

13

27%

5

10%

Maltby Hill Creek

43

33

77%

4%

4

8%

3

6%

6

15%

4

9%

Middle Creek

27

11

40%

1%

7

25%

4

16%

11

41%

5

20%

North Creek

130

92

71%

12%

30

23%

3

2%

32

25%

6

4%

North Creek Tributary

36

29

79%

4%

6

16%

1

2%

6

17%

1

4%

North Fork Perry Creek

38

24

63%

3%

3

9%

4

11%

8

20%

7

17%

Northwest Sammamish

5

3

74%

0.4%

1

11%

0.2

5%

1

17%

0.4

10%

Norway Hill Creek

5

5

84%

1%

0.5

9%

0.2

3%

1

12%

0.2

4%

Palm Creek

21

16

78%

2%

2

10%

1

5%

3

15%

2

7%

Parr Creek

62

36

57%

5%

10

17%

5

9%

16

26%

11

17%

Perry Creek

45

32

70%

4%

7

16%

2

3%

9

19%

5

10%

Queensborough Creek

44

31

71%

4%

6

13%

3

6%

8

19%

4

10%

Riverside Creek

39

32

81%

4%

4

11%

1

3%

6

14%

2

5%

Royal Anne Creek

70

50

70%

7%

13

18%

2

3%

15

21%

6

8%

Sammamish River

48

21

45%

3%

19

39%

4

8%

23

48%

3

7%

South Fork Perry Creek

19

14

75%

2%

2

12%

0.5

2%

3

14%

2

10%

Southeast Sammamish

9

6

68%

1%

2

20%

0.3

4%

2

23%

1

8%

Southwest Sammamish

2

2

100%

0.2%

0.0

0%

0.0

0.0%

0.0

0.0%

0.0

0.0%

Spring Stream

34

25

74%

3%

5

15%

2

7%

7

22%

2

5%

Valhalla Creek

11

11

95%

1%

0.2

2%

0.1

1%

0.4

3%

0.2

2%

Waynita Creek

39

27

69%

4%

6

17%

1

3%

8

20%

4

11%

West Fork Waynita Creek

17

16

95%

2%

0

2%

0.1

0.5%

0.5

3%

0.4

2%

1,107

762

69%

100%

171

15%

67

6%

238

21%

108

10%

Total

BOTHELL, WA URBAN CANOPY: APPENDIX

31

City of Bothell, WA Geographic Summary: Riparian Areas

Figure 26: Percent Urban Tree Canopy by Riparian Area

BOTHELL, WA URBAN CANOPY: APPENDIX

32

City of Bothell, WA Geographic Summary: Riparian Areas

Figure 27: Percent Possible Planting Area (Vegetation) by Riparian Area

BOTHELL, WA URBAN CANOPY: APPENDIX

33

City of Bothell, WA Geographic Summary: Parcels UTC metrics for Bothell, WA Parcels were generated in Acres and percent including Urban Tree Canopy (UTC Possible Planting Area Vegetation (PPA Vegetation), Possible Planting Area Impervious (PPA Impervious), Total Possible Planting Area (Total PPA), and Areas Unsuitable for Planting (Unsuitable). Due to the size of the dataset, tabular results were provided in GIS data format only.

Figure 28: Percent Urban Tree Canopy by Parcel BOTHELL, WA URBAN CANOPY: APPENDIX

34

City of Bothell, WA Geographic Summary: Parcels

Figure 29: Percent Possible Planting Area (Vegetation) by Parcel

BOTHELL, WA URBAN CANOPY: APPENDIX

35