APPENDIX D
Estimated Cost
Water Quality Project Cost Information
Total Annual Phosphorus Load lb Estimated Cost
Estimated Load Removed (LB) lb Cost per lb P Removed
Estimated Treatment Rate
1 2 2 5 x Habitat creation
x xpublic property no permitting x
private property xmoderate permitting
x complex permitting x Aesthetics
This is a relatively small erosion site, but represents a small point source of fine sediment loading to Lake Whatcom. There is good access from the Lowe Avenue right-of-way to complete the work. The project area is located close to a the prioritzed Geneva subbasin.
Project Summary Sheet
EXISTING CONDITIONS
There is an approximately 150 foot-long stretch of eroding and incising drainage channel located along Lowe Avenue on the south side of Lakeshore Drive. Upstream of the project site, where the drainage has a larger setback from the roadway, the channel is stable and erosion is not present. At the project location, the stream channel migrates closer to and parallels Lowe Avenue and becomes more confined and thus has less resilience to accomodate peak flows and scouring velocities. Downstream of the project site the County has placed quarry spalls along the channel to stabilize the bed.
$120,000
Photo 1. Looking south to incised channel running parallel to Lowe Ave. Photo 2. Vertical eroding channel bank.
PROPOSED IMPROVEMENTS
The project would include placement of large cobbles along approximately 150 linear feet of streambed to tie into the upstream limit of the County's previous quarry spall placement and laying back the left bank where possible to create a more stable cross-section to accomodate peak flows. The construction work could be completed from the left (west) bank where there is access. The project would incorporate revegetation with native plantings as allowed by regulatory reviewers and the utilities. There is a fire hydrant located near the project site and water and additional utilities could lie underneath the left bank of the project area.
PRIORITIZATION
Greater than 5 lb Phosph/
year removed
Less than 5 lb Phosphorus/
Public
education/visibility Greater than $100,000 / lbs
3.0 $120,000
3.0 $40,000
100%
Cost Effectiveness Score
Less than $100,000 per lb Phosphorus removed
Total Benefit Score Feasibility Score Combined Score Ancilary Benefits
Project Name Project ID Project Rank Estimated Cost
Water Quality Project Cost Information
Total Annual Phosphorus Load lb Estimated Cost
Estimated Load Removed (LB) lb Cost per lb P Removed
Estimated Treatment Rate
1 1 4 6 x Habitat creation
x x public property no permitting x
xprivate property moderate permitting
x complex permitting x Aesthetics
Silver Beach Creek is a priority subbasin area in the Lake Whatcom 2015-2019 Work Plan. The County and City together have invested in stormwater management and stream restoration to improve the water quality of stream runoff from the subbasin to Lake Whatcom. This project would complement those efforts.
Whatcom County
Capital Improvement Program Project Summary Sheet
Silver Beach Creek Channel and Bank Restoration
EXISTING CONDITIONS
Chronic stream bank erosion extends along Silver Beach Creek downstream of Hillsdale Road for an approximately 300 ft-long reach within residential properties located upstream of a large wetland complex. Erosion of bank material has generally been associated with sediment laden phosphorus loading to Lake Whatcom. The stream channel is starting to show signs of recovery in response to improved stormwater management upstream; however, the vertical stream banks will naturally continue to erode and export fine sediment downstream until they obtain more stable angles.
$450,000 199
Photo 1. Actively under-cutting bank. Photo 2. Channel bed aggradation adjacent to active bank eroson.
PROPOSED IMPROVEMENTS
The project would involve re-grading stream banks to a more stable angle and creating a stream channel cross-section with enough conveyance to accomodate changes to its hydrology and sediment supply. Large woody debris will be placed in the stream to create both physical habitat complexity as well as to create localized scour and settling areas for sediment. The streambanks and all disturbed areas will be replanted with native vegetation. This project would impact approximately 300 linear feet of stream, and would require easements from 2 parcels, as well as local and state permits. This project could be designed to be self-mitigating.
PRIORITIZATION
31
Greater than 5 lb Phosph/
year removed
Less than 5 lb Phosphorus/
year removed
Public
education/visibility Greater than $100,000 / lbs
Phosphorus removed
6.0 $450,000
6.0 $75,000
100%
Cost Effectiveness Score
Less than $100,000 per lb Phosphorus removed
Total Benefit Score Feasibility Score Combined Score Ancilary Benefits
D-2
Estimated Cost
Water Quality Project Cost Information
Total Annual Phosphorus Load lb Estimated Cost
Estimated Load Removed (LB) lb Cost per lb P Removed
Estimated Treatment Rate
1 1 4 6 x Habitat creation
x x public property no permitting x
xprivate property moderate permitting
x complex permitting x Aesthetics
Silver Beach Creek is a priority subbasin area in the Lake Whatcom 2015-2019 Work Plan. The County and City together have invested in stormwater management and stream restoration to improve the water quality of stream runoff from the subbasin to Lake Whatcom. This project would complement those efforts.
Project Summary Sheet
EXISTING CONDITIONS
Chronic stream bank erosion extends along this ephemeral stream tributary of Silver Beach Creek for an approximately 650 ft-long reach within residential properties located upstream of a large wetland complex. Erosion of bank material has generally been associated with sediment laden phosphorus loading to Lake Whatcom. The stream channel does not show signs of recovery and is actively incising and beginning to widen in places. Due to dense residential development, there are limited opportunties for adding flow control or detention upstream of this site. Reconfiguring the stream channel with a more stable cross-section would significantly reduce erosion and the export of fine sediment from the reach downstream.
$600,000
Photo 1. Small channel is actively incising but runs dry in summer. Photo 2. Small eroding channel continues through private properties.
PROPOSED IMPROVEMENTS
The project would involve re-grading the stream channel and banks to accomodate a more stable cross-section with enough conveyance to accomodate changes to its hydrology and sediment supply. Large woody debris will be placed in the stream to create both physical habitat complexity as well as to create localized scour and settling areas for sediment. The streambanks and all disturbed areas will be replanted with native vegetation. This project would impact approximately 650 linear feet of stream, and would require easements from 2 parcels, as well as local and state permits. This project could be designed to be self-mitigating.
PRIORITIZATION
Greater than 5 lb Phosph/
year removed
Less than 5 lb Phosphorus/
Public
education/visibility Greater than $100,000 / lbs
8.0 $600,000
8.0 $75,000
100%
Cost Effectiveness Score
Less than $100,000 per lb Phosphorus removed
Total Benefit Score Feasibility Score Combined Score Ancilary Benefits
Project Name Project ID Project Rank Estimated Cost
Water Quality Project Cost Information
Total Annual Phosphorus Load lb Estimated Cost
Estimated Load Removed (LB) lb Cost per lb P Removed
Estimated Treatment Rate
1 1 4 6 x Habitat creation
x x public property no permitting x
xprivate property moderate permitting
x complex permitting x Aesthetics
It is possible that most of the erosion likely to occur at this location has already occurred and because downstream road crossings appear to be exerting grade controls on the stream and causing some deposition of sediment, it is uncertain how much of an impact the project would have on reducing further fine sediment loading to Lake Whatcom. The project would benefit overall stability of the site, which would benefit the residential roadway to the west as well as residential properties that lie adjacent to the stream.
Whatcom County
Capital Improvement Program Project Summary Sheet
Coronado Creek Channel and Bank Stabilization
EXISTING CONDITIONS
There is severe bank erosion and channel incision along Coronado Creek downstream of Lewis Avenue and continuing along the stream channel until about midway to Columbus Avenue. The channel has already eroded down to the base-bedrock, and the banks are vertical and 15-20ft high in the project reach. Culvert crossings under roadways located both upstream and downstream of the project area actually function as channel bed grade controls that are somewhat limiting further potential for channel incision and headcut migration. Observations at downstream crossings indicate that Coronado Creek is fairly stable and the channel does not indicate signs of excessive sedimentation. It is unclear how much of the fine sediment being exported from the project site is actually being transported downstream of Fremont Avenue.
$500,000 228
Photo 1. View of channel incision down to bedrock. Photo 2. Looking upstream to unstable left emkbankment.
PROPOSED IMPROVEMENTS
This project would involve accessing the stream from the left bank sde in order to stabilize the streambed and left bank for an approximately 150-foot-long stretch, using a combination of large wood and rock to help stabilize the toe of slope and create steps in the channel. Access would be complicated and the project would significantly disturb existing mature vegetation, but the project would include revegetation with native plants.
PRIORITIZATION
33
Greater than 5 lb Phosph/
year removed
Less than 5 lb Phosphorus/
year removed
Public
education/visibility Greater than $100,000 / lbs
Phosphorus removed
7.0 $500,000
7.0 $71,000
100%
Cost Effectiveness Score
Less than $100,000 per lb Phosphorus removed
Total Benefit Score Feasibility Score Combined Score Ancilary Benefits
D-4
Estimated Cost
Water Quality Project Cost Information
Total Annual Phosphorus Load lb Estimated Cost
Estimated Load Removed (LB) lb Cost per lb P Removed
Estimated Treatment Rate
1 1 4 6 x Habitat creation
x x public property no permitting x
xprivate property moderate permitting
x complex permitting x Aesthetics
Priority subbasin area in Lake Whatcom 2015-2019 Work Plan; all project work would be conducted within the golf course.
Project Summary Sheet
EXISTING CONDITIONS
Austin Creek flows through the Sudden Valley golf course but much of the channel is entrenched and confined by the golf course land use and riparian vegetation is lacking. The golf course is situated on top of the historical alluvial fan of Austin Creek, which would be a natural depositional zone for sediment. While a planning study with Sudden Valley and the golf course may be necessary to identify and prioritze the best locations for stream and bank restoration and stabilization, a 1200 to 1500 foot-long length of stream channel just upstream of Lake Whatcom exhibits lacustrine habitat and could benefit from laying back the banks to a more stable angle and revegetating the banks with native vegetation to reduce the chronic and slow release of fine bank sediment into the stream and down to Lake Whatcom.
$200,000
Photo 1. Channelized segment of Austin Creek through the golf course. Photo 2. Vertical banks with minimal vegetation.
PROPOSED IMPROVEMENTS
The project would involve re-grading the stream banks to accomodate a more stable cross-section. The streambanks and all disturbed areas will be replanted with native vegetation, as coordinated with the golf course and regulatory reviewers.
PRIORITIZATION
Greater than 5 lb Phosph/
year removed
Less than 5 lb Phosphorus/
Public
education/visibility Greater than $100,000 / lbs
8.0 $200,000
8.0 $25,000
100%
Cost Effectiveness Score
Less than $100,000 per lb Phosphorus removed
Total Benefit Score Feasibility Score Combined Score Ancilary Benefits
Project Name Project ID Project Rank Estimated Cost
Water Quality Project Cost Information
Total Annual Phosphorus Load lb Estimated Cost
Estimated Load Removed (LB) lb Cost per lb P Removed
Estimated Treatment Rate
1 2 4 7 x Habitat creation
x xpublic property no permitting x
private property moderate permitting
x x complex permitting x Aesthetics
Euclid Park is located within the Geneva urban growth area and within a prioritized subbasin area in the Lake Whatcom 2015-2019 Work Plan. Geneva is located within Bellingham jurisdiction, however, the site is located on public land, simplifying the easement process, and there is fairly good access to the site from Euclid Avenue to the west.
Whatcom County
Capital Improvement Program Project Summary Sheet
Euclid Creek Restoration and Revegetation
EXISTING CONDITIONS
There is 120 foot-long reach of Euclid Creek within Euclid Park experiencing minor streambed and bank erosion along a portion of the channel where it parallels Euclid Avenue. Erosion appears to be triggered by a combination of altered hydrology and increased peak flows as well as disturbance caused by pedestrian access to the site.
English ivy is starting to choke native vegetation on the left (west) bank and channel and bank restoration here could serve a double-purpose of stabilizing the stream as well as helping to preserve native vegetation and habitat within the park.
$300,000 218
Photo 1. Looking upstream to eroding left bank. Photo 2. Looking upstream to erosion and invasive vegetation on the left bank.
PROPOSED IMPROVEMENTS
The project would involve accessing Euclid creek from the left (west) bank and laying back the left bank in places to accomodate a more stable channel cross-section.
The project is expected to impact approximately 120 linear feet of Euclid Creek. All project work can focus on the left bank and stream channel and limit disturbance to the right bank. Large woody debris will be placed in the stream to create both physical habitat complexity as well as to create localized scour and settling areas for sediment. Invasive vegetation that is starting to become a problem from this site, should be removed prior to construction. The streambanks and all disturbed areas will be replanted with native vegetation, as coordinated with the park and regulatory reviewers. Construction access from Euclid Avenue would create some traffic impacts during construction there.
PRIORITIZATION
36
Greater than 5 lb Phosph/
year removed
Less than 5 lb Phosphorus/
year removed
Public
education/visibility Greater than $100,000 / lbs
Phosphorus removed
5.0 $300,000
5.0 $60,000
100%
Cost Effectiveness Score
Less than $100,000 per lb Phosphorus removed
Total Benefit Score Feasibility Score Combined Score Ancilary Benefits
D-6
Estimated Cost
Water Quality Project Cost Information
Total Annual Phosphorus Load lb Estimated Cost
Estimated Load Removed (LB) lb Cost per lb P Removed
Estimated Treatment Rate
1 2 4 7 x Habitat creation
x public property no permitting x
xprivate property moderate permitting
x x complex permitting x Aesthetics
This erosion location is relatively small and is located along an unmapped drainage channel that is likely ephemeral. However, it does present a point source of fine sediment supply that could be addressed with minimal capital investment.
Project Summary Sheet
EXISTING CONDITIONS
There is an approximately 50-foot length of eroding embankment below (east of) Lowe Avenue on the north side of Lakeshore Drive along the left bank of an unnamed tributary drainage in the Donovan basin. The embankment is vertical and oversteepened and is starting to pose a threat to the structural integrity of the Lowe Avenue Roadway prism, located just north of the limit of the road that is maintained by County. The tributary drainage is ephemeral and not designated as fish-bearing. The embankment is too steep to support vegetation establishment, and will continue to chronically erode, exporting fine sediment downstream and eventually likely to cause slumping of the Lowe Avenue roadway above.
$300,000
Photo 1. View of eroding left embankment downstream of driveway crossing. Photo 2. View of vertical, eroding embankment below private roadway.
PROPOSED IMPROVEMENTS
The project would involve the installation of a bioengineered revetment including a combination of large woody debris, rock, and vegetation to provide a stable toe of embankment and allow vegetation to anchor the upper bank to avoid further erosion and destabilization. Because the project lies just outside the limit of the roadway maintained by the County, there would need to be some planning and coordination for access and easements with property owners. There would be temporary traffic and access impacts to local residents during construction.
PRIORITIZATION
Greater than 5 lb Phosph/
year removed
Less than 5 lb Phosphorus/
Public
education/visibility Greater than $100,000 / lbs
3.0 $300,000
3.0 $100,000
100%
Cost Effectiveness Score
Less than $100,000 per lb Phosphorus removed
Total Benefit Score Feasibility Score Combined Score Ancilary Benefits
Project Name Project ID Project Rank Estimated Cost
Water Quality Project Cost Information
Total Annual Phosphorus Load lb Estimated Cost
Estimated Load Removed (LB) lb Cost per lb P Removed
Estimated Treatment Rate
2 2 4 8 x Habitat creation
public property no permitting x
xprivate property moderate permitting
x x x complex permitting x Aesthetics
Relative to other identified stream problem areas, this project is a fairly small site with only moderate levels of erosion, yet significant private property coordination would be required to discuss access and use impacts during construction.
Whatcom County
Capital Improvement Program Project Summary Sheet
Agate Bay Trib Channel and Bank Resotration
EXISTING CONDITIONS
This unnamed tributary of Agate Bay was initially screened out from the study due to relatively low levels of upper basin development. However, the stream channel passes through a residential area between Northshore Drive and Lake Whatcom. There is an approximately 120 foot-long stretch of stream experirencing bed and bank erosion downsteam of Northshore Drive. Channel erosion is likely related to local impacts within or near the proposed project area, the effect of the culvert crossing under Northshore Drive, and confinement and armored channel banks associated with the residential area. The county could collaborate with residential homeowners to improve conditions for not only reduced stream erosion, but also habitat and aesthetics.
$450,000 205
Photo 1. Right bank erosion downstream of Northshore Drive. Photo 2. Right bank erosion continues downstream of Northshore Drive.
PROPOSED IMPROVEMENTS
The project would involve re-grading the stream channel and banks to accomodate a more stable cross-section. Large woody debris will be placed in the stream to create both physical habitat complexity as well as to create localized scour and settling areas for sediment. The streambanks and all disturbed areas will be replanted with native vegetation, as coordinated with the private property owners and regulatory reviewers. The project would require easements from 2 parcels and along approximately 120 linear feet of stream, in order to work just upstream of the private road crossing between Northshore Drive and Lake Whatcom. Adding further stream restoration downstream of that private road crossing would impact two additional parcels.
PRIORITIZATION
38
Greater than 5 lb Phosph/
year removed
Less than 5 lb Phosphorus/
year removed
Public
education/visibility Greater than $100,000 / lbs
Phosphorus removed
4.0 $450,000
4.0 $113,000
100%
Cost Effectiveness Score
Less than $100,000 per lb Phosphorus removed
Total Benefit Score Feasibility Score Combined Score Ancilary Benefits
D-8
Estimated Cost
Water Quality Project Cost Information
Total Annual Phosphorus Load lb Estimated Cost
Estimated Load Removed (LB) lb Cost per lb P Removed
Estimated Treatment Rate
2 2 4 8 x Habitat creation
xpublic property no permitting x
private property moderate permitting
x x x complex permitting x Aesthetics
low sediment/phosphorus reduction return for a relatively expensive project
Project Summary Sheet
EXISTING CONDITIONS
There is minor stream and bank erosion located near the inlet and outlet of a 24" diameter culvert that is likely undersized.
$650,000
Photo 1. Sedimentation upstream of culvert indicates potential capacity issues. Photo 2. Flow concentration at culvert outlet likely creates localized scour.
PROPOSED IMPROVEMENTS
Project could involve replacing likely undersized 24" Diam culvert with a larger fish-passable culvert and include instream wood/rock placement to promote natural channel grade control to replace the grade control function of the existing culvert. By installing a crossing with a larger span, and designing for geomorphic processes, project could prevent flow concentration that potentially induces erosion downstream. Culvert replacement would result in significant traffic impacts on Lake Louise Rd. Easements from two parcels (one upstream and one downstream of the culvert) would be required.
PRIORITIZATION
Greater than 5 lb Phosph/
year removed
Less than 5 lb Phosphorus/
Public
education/visibility Greater than $100,000 / lbs
3.0 $650,000
3.0 $217,000
100%
Cost Effectiveness Score
Less than $100,000 per lb Phosphorus removed
Total Benefit Score Feasibility Score Combined Score Ancilary Benefits