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05 Draft PWS Sources Sought 1.pdf

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July 20, 2021, 5:37 p.m.
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PERFORMANCE WORK STATEMENT (PWS) Truckee Basin Water Management Options Pilot Study—Hydrology and Hydraulic Analyses Contract May 2021 1.0 Scope 1.1 Objective The objective of this Performance Work Statement (PWS) is to define the tasks and deliverables for the Contractor to complete the Reclamation Truckee Basin Water Management Options Pilot Study Hydrology and Hydraulic analyses. 1.2 Background The purpose of this contract is to provide hydrology and hydraulic analyses to support the Truckee Basin Water Management Options Pilot (WMOP) study. The hydrology analyses needed for the WMOP study are Rain and Snowmelt Flood Frequency Curve Updates. The hydraulic analyses needed for the WMOP study are hydraulic model calibrations & validations and a Channel Capacity Analysis with inundation mapping. Further detail is provided below. 1.2.1 Truckee Basin Water Management Options Pilot Study The Truckee River Basin encompasses about 3,060 square miles in California and Nevada. Water in the basin originates high in the Sierra Nevada mountains at elevations over 10,000 feet. The Truckee River flows approximately 121 miles from the outlet of Lake Tahoe to its terminus at Pyramid Lake. While 90% of the flow and virtually all of the Basin’s water storage lie in California, the vast majority of water demands are in Nevada. There are three Reclamation Projects within the WMOP study area: the Washoe Project (Stampede and Prosser dams and reservoirs), the Newlands Project (Lake Tahoe Dam, Derby Dam, the Truckee Canal and Lahontan Dam and Reservoir), and the Truckee Storage Project (Boca Dam and Reservoir). There are three other dams within the Truckee Basin: Donner and Independence Lake dams which are owned and operated by Truckee Meadows Water Authority for water supply, and Martis Creek Reservoir which is owned and operated by the U.S. Army Corps of Engineers exclusively for flood control purposes. Drought and flooding are becoming more common in the Truckee Basin. The extreme variability from year to year in terms of winter precipitation, snowpack, and runoff make it very challenging for water managers, including Reclamation and the Non-Federal Partners, to adapt and plan for water supplies due to how federally owned storage reservoirs must be operated for flood risk reduction. Even in large runoff years in the Truckee Basin, the same flood control diagrams (i.e., rule curves) and snowmelt parameters can often prevent filling into the flood space until it is too late in the season. Oftentimes, during years with significant snowpack, by the time filling is finally allowed into the flood storage space (based on the high snowmelt parameters) the runoff has receded to a level that some reservoirs aren’t always able to be filled to capacity. Flood and reservoir refill operations are governed by the Water Control Manual for the Truckee River Basin Reservoirs Truckee River, Nevada and California (1985) issued by the US Army Corps of Engineers (USACE). The manual suffers from outdated rule curves, inflexible storage requirements, constrained reservoir release thresholds, and a constrained downstream regulation goal at Reno. It also does not reflect the Truckee River Operating Agreement (TROA), flood mitigation projects completed in Reno and Sparks since 1985, the crest raise at Reclamation’s Stampede Dam, or the parapet wall added to Reclamation’s Prosser Dam. The purpose of the Truckee Basin WMOP study is to develop flexible flood risk reduction criteria without increasing downstream flood risk. The WMOP study will evaluate Forecast Informed Reservoir Operations, flexible rule curves, and changes to downstream regulation goals. The reservoirs Processor, Boca, Stampede and Martis governed by the Water Control Manual could benefit from the advanced flexible operations. This WMOP study will then be documented in a Viability Assessment document and provided to the USACE for a subsequent update to the Water Control Manual. The hydrology and hydraulic analyses proposed in this PWS will support the Truckee Basin WMOP study. The above paragraphs about the WMOP study provide background for this PWS. The following subsubsections Rain and Snowmelt Flood Frequency Curve Updates and Channel Capacity Analysis provide the context for the tasks in this PWS. 1.2.2 Rain and Snowmelt Flood Frequency Curve Updates The original rain and snowmelt flood frequency curves are found in the 1985 Water Control Manual. The unregulated rain and snowmelt frequency curves were developed for the following locations: Boca Reservoir, Prosser Reservoir, Martis Reservoir, Truckee River at Farad, and Truckee River at Reno. Stampede Reservoir’s rain and snowmelt flood frequency curves were not developed in the 1985 Water Control Manual because Stampede and Boca Reservoirs are in series and share flood storage allocation proportionally between the reservoirs. The Boca Reservoir is downstream of Stampede Reservoir and they do not have much local inflow in between and share similar drainage areas. The datasets used to develop these rain and snow flood frequency curves include the period from 1901 to 1983. The rain and snowmelt flood frequency curve updates are needed to add flow records (~37 years) to the previously performed analysis by the USACE. The fitted probability distribution function used for flood frequency curve development is subject to uncertainty without a substantial stream flow record length. The additional years of flow records will help reduce the uncertainty of the rain and snowmelt flood frequency curves. 1.2.3 Channel Capacity Analysis Substantial work has already been done to develop hydraulic models that simulate the Truckee Meadows area (West Reno to Vista gage) and the Vista gage to Wadsworth gage reach of the Truckee River. The hydraulic models are based on the Hydrologic Engineering Center (HEC)-River Analysis System (RAS). The Truckee Meadows area model is a full 2D model with both steady and unsteady state conditions. The Vista gage to Wadsworth gage model is a 1D model with steady state conditions that can be converted to unsteady flow with updated hydrology. The HEC-RAS models developed are currently being used for a Federal Emergency Management Agency (FEMA) Physical Map Revision with the 1% annual chance exceedance flow as the focus. The hydraulic models will need to be calibrated and validated for flows around 6,000 cfs for this analysis. As part of the FEMA analysis, the Truckee Meadows area model was compared to high water marks during the 2006 event which was approximately 14,000 cfs (roughly a 50 year event). The current model is run with diffusion wave equations under the RAS 6.0.X Beta 3 release with roughness and other parameters calibrated against high water marks. Diffusion wave is used over full momentum because it had better performance especially around bridges and in wide floodplain spreading situations. The Vista to Wadsworth model is run under a 1D steady flow conditions to meet FEMA guidelines for mapping. The Reno gage is a control point of interest for the Truckee Basin WMOP study because the current Water Control Manual adheres to a target (control) of 6,000 cfs at the Truckee River at Reno gage. If modeling results show a greater capacity exists, the control of 6,000 cfs could be adjusted higher and allow for more flexibility in operation of the reservoirs. The analysis will include inundation maps for flows incrementing from 6,000 cfs to 14,000 cfs at the Truckee River at Reno gage. The Channel Capacity Analysis will serve to identify the channel capacity, limiting cross sections, and breakout points for the Truckee Meadows area and Vista gage to Wadsworth gage reach. 2.0 References & Materials The following documents shall be provided to the Contractor: (1) Water Control Manual - Truckee River Basin Reservoirs Truckee River, Nevada and California (1985) (2) Truckee Meadows General Reevaluation Report Truckee River, Nevada - Attachment A Hydrology Report (2012) (3) Engineer Manual 1110-2-1415 Hydrologic Frequency Analysis (1993) (4) Guidelines for Determining Flood Flow Frequency Bulletin 17C (2019) (5) HEC-SSP Statistical Software Package User’s Manual (6) TRFMA’s HEC-RAS model documentation (7) Technical Service Center Manuals and Standards: Flood Inundation Mapping (2019) (8) Reclamation’s Visual Identity Guidelines for Publications, Reports and Template (9) Comment tracking spreadsheet The following models shall be provided to the Contractor: (1) Truckee Meadows area 2D HEC-RAS model (2) Vista gage to Wadsworth gage reach 1D HEC-RAS model 3.0 Tasks The Contractor shall perform the following tasks for the Bureau of Reclamation (Reclamation), Lahontan Basin Area Office (LBAO) to support the Truckee Basin WMOP study. These tasks include rain and snowmelt flood frequency curve updates and channel capacity analysis. 3.1 Task 1 – Project Management and Administrative (1) The Contractor shall conduct all managerial and administrative duties to manage this contract. This includes project management and oversight of contractor activities, staff, and resources. (2) The Contractor shall develop a Project Management Plan which includes the tasks and deliverables schedule for discussion, no later than one (1) month after contract award, ensuring all appropriate tasks and predecessors are identified. The schedule should identify milestones for each product. This schedule will be revisited at least monthly and updated as needed. (3) The Contractor shall prepare and submit monthly status reports and invoices. 3.2 Task 2 – Meetings The Contractor shall participate in meetings as necessary. The meeting frequency and participants are defined below. 3.2.1 Kickoff Meeting Within one month of contract award, the Contracting Officer (CO), Contracting Officer’s Representative (COR), and LBAO’s Project Manager will schedule a Kickoff Meeting with the Contractor via webinar to discuss t… Show All