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HomeMy WebLinkAboutResolution_WSE TO 2_Hanson PitsKITTITAS COUNTY DEPARTMENT OF PUBLIC WORKS AGENDA STAFF REPORT AGENDA DATE: September 15, 2020 ACTION REQUESTED': Request to Approve a Resolution to Authorize the Chair's Signature on Watershed Sciences and Engineering Task Order No. 2 for a Hanson Pits Channel Migration and Avulsion Risk Assessment BACKGROUND: Public Works (PW) has an on-call task order contract with Watershed Sciences and Engineering (WSE) for hydraulic and hydrology engineering services (pursuant to April 2020 procurement effort). PW requires an assessment of channel avulsion and migration risk to inform land management decisions at the County -owned Hanson Pits, spray fields, and Stewart properties. These land management decisions include restoration opportunities in support of an Advanced Mitigation Strategy for Kittitas County Environmental Impacts. WSE has previously conducted technical analyses in this reach of the Yakima River and has developed a 2- dimensional hydraulic model that will be utilized in this effort. WSE is offering to complete the channel migration and avulsion risk assessment for $73,355. The contract value exceeds the authority of the Public Works Director. INTERACTION: Public Works RECOMMENDATION: Approve the Resolution to Authorize the Chair's Signature on WSE Task Order No. 2 for Hanson Pits Channel Migration and Avulsion Risk Assessment. HANDLING: Return one original to Public Works ATTACHMENTS: Resolution, Task Order LEAD STAFF: Arden Thomas, Water Resource Manager BOARD OF COUNTY COMMISSIONERS COUNTY OF KITTITAS STATE OF WASHINGTON RESOLUTION NO. 2020 - AUTHORIZING THE CHAIR'S SIGNATURE ON WATERSHED SCIENCES AND ENGINEERING TASK ORDER NO. 2 — HANSON PITS CHANNEL MIGRATION AND AVULSION RISK ASSESSMENT WHEREAS: Kittitas County Public Works procured on-call professional hydraulic and hydrology engineering services from Watershed Sciences and Engineering (WSE) consistent with state law and local purchasing policies in April 2020; and WHEREAS: WSE has previously conducted technical analyses and developed 2-dimensional hydraulic model for the Yakima River; and WHEREAS: The value of Task Order No. 2 exceeds the contract authorization amount currently provided the Public Works Director; and WHEREAS: The Hanson Pits risk assessment is required to inform land management decisions; NOW, THEREFORE BE IT RESOLVED that the Board of County Commissioners, in the best interest of the public, does hereby authorize the Chair's signature on WSE Task Order No. 2 in the amount of $73,355. DATED this 15th day of September 2020, at Ellensburg, Washington. Attest: ❑ Clerk of the Board- Julie Kjorsvik ❑ Deputy Clerk of the Board- Mandy Buchholz BOARD OF COUNTY COMMISSIONERS KITTITAS COUNTY, WASHINGTON Brett Wachsmith, Chairman Laura Osiadacz, Vice -Chairman Cory Wright, Commissioner rn<r. ,,r KITTZTAB COUN'7[°� DEPARTMENT OF PUBLIC WORKS KI J FIT 11( (11 NTP Formal Task Order Document WATERSHED Science & Engineering Task Order Number Maximum Amount Payable $ 73,355 7 Completion Date 2/26/2021 The general provisions and clauses of the 2020 — 2022 Task Order Master Contract for Hydraulic and Hydrology Professional Consulting Services shall be in full force and effect for this Task Order. Location of Project: Kittitas County Project Title: Hanson Pits Channel Migration and Avulsion Risk Assessment Description of Work: See attached Scope of Work Cost Breakdown: See attached Scope of Work Completion Date: Agency Signature: Date: Consultant Signature: M1 Date: 9/2/2020 Scope or Services Hanson Pits Channel Migration and Avulsion Risk Assessment Kittitas County Flood Control District (County) is advancing a strategy to identify and pursue funding for projects where the County can decommission obsolete flood control structures and improve geomorphic processes that create and sustain high quality salmon habitat. The Hanson Pits levee and downstream private berm have been identified as structures that may no longer be needed and recent property acquisitions landward of these facilities presents an opportunity to remove or modify the structures and restore floodplain function. The County owns the Hanson Pits (as series of old gravel barrow pits) and several large agricultural parcels immediately downstream. The Hanson Pits levee and the private berm are both in poor condition and likely will fail sometime in the future; however, they currently provide limited protection for the properties by preventing the river from avulsing or migrating into them. The County desires to develop and implement a plan that will allow part or all of the Hanson Pits levee and private berm to be decommissioned, the borrow pits and portions of the floodplain to be reconnected to the river and restored for habitat, and continued agricultural activities on the downstream parcels. The County is concerned that removing all or portions of the levee and berm may allow the river to avulse or migrate into the pits and the downstream properties. This risk needs to be understood and incorporated into land use planning. Channel migration may be okay, so long as ecologic function associated with wetland, riparian, and instream habitat is not degraded and agricultural activities can continue on portions of the downstream properties. The County has requested Watershed Science & Engineering (Consultant) to conduct an avulsion / channel migration risk investigation to predict how the river may respond to various levee/berm decommissioning alternatives for the purpose of helping the County make an informed decision as to how best to proceed with the decommissioning / restoration project. The scope of the WSE investigation is described in the tasks below. TASKS Data Collection and Review The consultant shall collect and review existing data needed to complete the avulsion / channel migration investigation. Information will include but not be limited to: • LiDAR data (2008/2011 and if available 2019) • Technical documents including recent hydraulic and habitat reports developed as part of the 2015 Yakima River Corridor Plan • SRH2D hydraulic model developed for the 2015 Yakima River Corridor Plan • Current and historical aerial photographs and maps • Surficial soil data • Yakima River discharge data • River sediment grain size, supply, transport, and deposition data • Design data for levees and revetments Assumptions: • The Consultant possesses many of these materials due to their role in the 2015 corridor study. • The County will assist the Consultant in obtaining materials as needed. • The USGS and the DNR collected UDAR in 2019 for eastern Washington, but it may not yet be available. 2. Project Goals, Objectives, Constraints and Evaluation Criteria A meeting will be held with County staff to define project goals, objectives, constraints, and alternative evaluation criteria. • Goals are high level statements that describe what the project will accomplish. • Objectives are more focused statements that describe specific outcomes that the project should deliver. • Constraints are limitations that may restrict certain actions. • Evaluation Criteria are metrics used to evaluate the degree to which alternatives meet the project objectives. Deliverables: • List of draft project goals, objectives, constraints, and evaluation criteria provided to the County for review. • List of final project goals, objectives, constraints, and evaluation criteria will be presented in the project report. Assumptions: • This will be a video conference call meeting that will last 1 hour and will be led by the Consultant. 3. Bathymetric and Topographic Survey The consultant will complete a bathymetric survey of the Hanson Pits gravel extraction ponds and will create a topographic map for the floor of each cell. Deliverables: • Bathymetric survey data in an AutoCAD file. • Topography for the floor of each cell. Assumptions: • Consultant will provide all equipment required to complete the survey. 4. Field Reconnaissance Consultant and County staff shall conduct a field reconnaissance of the project site. The team shall examine: • Condition and characteristics of the existing Hanson Pits Levee and downstream private berm. • Condition and characteristics of the borrow pits. • Geomorphic characteristics of the active channel in the vicinity of the project site, including bed and bank morphology and large wood characteristics. • Geomorphic characteristics of the floodplain, including floodplain surface topography, forest stand characteristics, and the location of man-made facilities. During the reconnaissance Consultant and County staff shall discuss the project and possible alternatives in relation to the stated goals, objectives, and constraints. Deliverables: • Observations and photographs to be included in the project report. Assumptions • The inspection will last three to four hours. • A member of the County survey crew will participate for one hour to discuss the bathymetric survey. • Physical feature condition assessments will be qualitative. No quantitative testing will occur (e.g. soil borings, etc.). 5. Hydrology Review The Consultant shall review and update hydrologic information generated for the 2015 corridor investigation. They shall update annual instantaneous peak flow flood frequency values as well as review the characteristics of the irrigation -driven "flip-flop" that occurs in the river each year between May and September, whereby high and low flows do not correspond to their natural timing. The key outcomes of this task will be to generate flood hydrographs to use in the hydraulic model and to associate observed historical geomorphic changes to recorded peak flood and sustained irrigation summer flip-flop high flows. Deliverables: • Updated annual instantaneous peak flood frequency discharges. • Updated understanding of the timing, magnitude, and duration of the irrigation -driven "flip-flop". • Identification and description in the project report of events that have caused significant geomorphic. • change. Assumptions: • Deliverables will be included in the project report 6. Hydraulic Modeling The Consultant shall review and update the existing SRH2D hydraulic model of the project reach which was created for the 2015 corridor plan. The consultant will: • Update the model topographic mesh using the 2019 LiDAR and surveys from Task 3 and updated publicly -available topography data, if available. • Recalibrate the model if recent flood highwater marks and peak flow data are available. If the data are not available, WSE will use engineering judgement to set model parameters. • Run the model to estimate hydraulic conditions for up to four flow events. Two events will represent floods that are known to initiate geomorphic change, one will represent a typical summer prolonged flip-flop flow, and one a habitat flow. • Model geometry will be modified to test up to four different Hanson levee, private berm, and floodplain reconnection alternatives for the four aforementioned flow events. Model results will be: o Compared to the existing condition hydraulic model runs to identify hydraulic changes attributable to the proposed alternatives. o Used to evaluate hydraulic patterns and forces in order to predict future geomorphic change including channel avulsion and migration potential. Deliverables: • Model results in the form of GIS figures and tables. Assumptions: • If 2019 LiDAR can be obtained, the Consultant shall use it to update the SRH2D model geometry in the vicinity of the project. • Deliverables will be included in the project report. 7. Geomorphic Assessment The consultant shall conduct a geomorphic assessment to: • Identify and characterize the geomorphic processes that currently shape the project reach and how they are affected by the existing Hanson Pits levee and private berm. • Identify past hydrologic events have been responsible for generating significant geomorphic change to discuss the relationship between flow and the historical geomorphic evolution of the reach • Determine whether a river avulsion into the Hanson Pits and/or downstream floodplain is likely if no actions are taken. If an avulsion is likely, determine the likely river path, impact to public and private parcels, and road, rail, flood protection infrastructure. • Determine whether the channel is likely to migrate into the Hanson Pits or downstream floodplain if no actions are taken. If significant channel migration is likely, determine the likely migration path and rate, impact to the public and private parcels, and road, rail and flood protection infrastructure. Estimate how the river is likely to respond to each for the four project alternatives (see next task). Predictions will made for two future time periods — 5 years and 25 years in the future. Because predictions are uncertain, the Consultant will provide an estimate of the range of possible geomorphic change that may occur as opposed to a single predicted outcome. Deliverables: Text and figures that present the results of the geomorphic investigation to be included in the project report. Assumptions: • Future geomorphic response predictions are inherently uncertain; therefore, the Consultant's predictions are approximate and are to serve as general information for the purpose of comparing the alternatives and defining uncertainty. • Geomorphic assessment will require up to one day of additional field data collection to assess geomorphic conditions related to avulsion and migration. 8. Alternative Concepts and Evaluation The consultant, in consultation with County staff, shall identify up to four project alternatives. The alternatives shall include but not be limited to: 1. Remove the Hanson Pits Levee and private berm completely. 2. Remove portions of the Hanson Pits Levee and private berm. Up to three partial levee / private berm removal options will be tested. 3. In combination with 1 and 2 above, the Consultant will include simple floodplain reconnection actions in the alternatives. As part of Tasks 6 and 7 above, the Consultant shall run the hydraulic model for each alternative and use the results help inform the future geomorphic response predictions. An alternative evaluation matrix will be created to compare the four alternatives using the evaluation criteria developed in Task 2. Deliverables: • Simple concept sketches representing each project alternative. • Descriptions of the alternatives. • Descriptions of anticipated geomorphic change and avulsion / channel migration risk. • Evaluation matrix. Assumptions: • This task will allow the County to identify a range of options that will meet the stated goals and objectives. Phase 2 of this effort will be to engage stakeholders as appropriate to help select/refine a preferred alternative. Phase 2 is not included in this task assignment. • Deliverables will be included in the project report. • Cost Estimates will not be prepared for the alternatives. • Consultant and County staff will participate in a 2 -hour video conference call to identify the four alternatives to test. 9. Meeting with County Staff to Review Investigation Results Following Task 8, the Consultant and County staff shall participate in a 2 -hour video conference call to review and discuss the results of the investigation. Meeting outcomes shall include: • Determining whether alternatives should be refined, or if additional alternatives should be considered and evaluated. • Selection of the alternative that appears to meet project goals and objectives. Deliverables: • Power Point presentation of the investigation results. Assumptions: • Alternative refinements or creating / testing additional alternatives may require a contract modification. • Consultant and County staff shall participate in a 2 -hour video conference call to review the results. 10. Technical Report The results of the investigation shall be summarized in a technical report which will be provided to the County for review. The technical report will present: • Project goals, objectives, and constraints. • Descriptions of existing hydrologic, hydraulic and geomorphic conditions. • Four alternatives including a concept -level overview sketch of each. • Anticipated alternative performance including discussion of avulsion and channel migration potential. • Evaluation matrix and the rationale for the selection of a preferred alternative. Deliverables: • Draft and final report. Assumptions: • County staff will review the draft report and provide a single set comments to the Consultant. • The Consultant will address the County comments in the final report. 11. Administration The consultant will perform typical administrative duties including communicating regularly with the County's project manager, monitoring schedule and budget, and submitting monthly invoices. Schedule TBD �$- WATERSHED — SCIENCE & ENGINEERING 110 Prefontaine Place South, Suite 508 Seattle, WA 98104 Tel. (206)521,3000 Estimate of Professional Services Prepared for: Kittitas County Project: Yakima River Hanson Pits Channel Migration/Avulsion Assessment Date: 8/212020 Prepared By: Jeff Johnson I Dan Scott TASK DESCRIPTION WSE PGS TWala ata Collection and Keview 1,828 1,928 2. ProjeUGOalS, Objectivee, onsran an vduao0n n¢na 1,M3 ypy3 at ymetnc and I OpWrap Ic uN9y $337 14,520 14,89 4. Held econnalssance 3.921 1 Hydrology Keviw $125 ,125 6. Hydraulic Modelng $10,419 $10,419 e0m0rp ¢ ASSeSSMent -------- T1 -1-0S4— 11,094 ma Ive GOnCePS and tvaluafidn a, 4 4 9. ee ng mth CountyO Review nvestlga0on esus 2.9]8 $2.976 10. ec nCa epon $597 9,F97-- 11.mIN ra Ion otal Labor Coat Per Fiml TOTAL LABOR COST $54.M8 1,520 69,Ti8 Direct Expense Detail Cost WSE $ 280 PGS $ 3,857 54,978 18,377 Towl WATERSHED SCIENCE A, ENGINEERING 110 Prefontaine Place South, Suite 508 Seattle, WA 88104 Tel. (206)521-3000 Estimate of Professional Services Prepared for: Kitlitas County Project: Yakima River Hanson Pits GIS Tech Contract Adm. Channel Migration/Avulsion Assessment Date: September 2, 2020 Prepared By: Jeff Johnson/Dan Scoff TASK DESCRIPTION Principal Sr. Ent.t Hey Sr. cep.. Eng, I GIS Tech Contract Adm. Totals Data O e[ Ion and Revies, 2 0 B 1, z. protect Goam. ubjectives. uorstraints and Evaluation Untem, 4 2 3. Sathymencan opograP is SunH,y 06 1 1 337 4. rieac, Ketonnaussance B B 9 3,821 5. molly Review 4 12 2,125 3. Hydraulic Modeling 4 4 8 10,410 7. eonmrp Ic eee55me0 4 60 24 11,op4 Alternative Concepts and Evaluation 20 t 0. 4 Meeting wiln County Stan to Revim Investg2ton ROMWIS B a e 2,116 10. Technical epo 16 4 24 24 8,50] AdMiniStreatan Total Hours eM Direct labor Cost (OL) Labor Rate (Mr) TOTAL LABOR COST 7551 $197.0f $14e]] sol 1838 $1,435 120,01 12720 1 $15264 200 0 1 IIIIIA21$76100 $22,&53 0,012.0 1Ba.W $0 $170 54,698 Direct Expense Detail Unit Rare Cost Mileage 500 $0.560 $ 280 Total $ 280 Cost Summary Total Labor $ 54,898 Total Direct Expenses $ 280 Total $ 54,878 Puific Geomtlic services, Inc. Estimate of Professional Services