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I <br />IPRRIP - ED OFFICE MEMORANDUM <br />1 <br />TO: <br />BEORN COURTNEY <br />FROM: <br />JASON FARNSWORTH <br />SUBJECT: <br />RESERVOIR FEASIBILITY AND DESIGN <br />DATE: <br />SEPTEMBER 12, 2008 <br />CC: <br />' A typical reservoir feasibility and design process (including timeline and major task items) is presented <br />below. <br />1 <br />0 <br />0 <br />• PHASE I — PREFEASIBILITY STUDY (6 -9 Months & $40,000 to $60,000) <br />o Preliminary Hydrologic Investigation — Developed from readily available <br />USGS 1:24,000 Quadrangle Maps, FSA NAIP aerial imagery, and NRCS <br />SSURGO soil survey data. <br />• Preliminary Sediment Yield Analysis — Developed from RUSLE and <br />area/delivery curves or a simple model like the USEPA's STEPL model. <br />• Preliminary Reservoir Routing — Based on hydrologic investigation, estimated <br />sediment yield, and stage- storage relationship developed from USGS Quadrangle <br />Maps. <br />• Preliminary Water Quality Investigation — Preliminary reservoir water quality <br />response to sediment and nutrient loadings using EUTROMOD or similar model <br />• Preliminary Geotechnical Investigation — Two to four borings along proposed <br />dam centerline. May need to be conducted in the spring or late fall to avoid crop <br />damages. <br />• Preliminary Dam Structure Design — Will range in complexity and cost <br />depending on principal and auxiliary spillway configurations. <br />• Transportation Impact Identification - County road closures are a huge issue. <br />A county can refuse to close or even move a county road. This has rendered <br />several reservoir projects in infeasible. <br />• Environmental and Cultural Resources Screening — Preliminary consultation <br />with USFWS, USACE and SHPO. Windshield wetland and T &E Species survey <br />• Preliminary Project Economic Analysis — Cost estimating and return on <br />investment. <br />• Landowner Information Meeting — Early identification of opposition and <br />beginning of coordination. <br />PHASE II — FEASIBILITY STUDY (12 -15 MONTHS & $150,000 - $250,000) <br />• Detailed Topographic Survey (Up to Top of Dam Elevation) — Typically more <br />cost - effective to have site flown than to do a ground survey. <br />• Detailed Hydrologic Investigation — Detailed hydrology model (HEC -HMS or <br />similar). Even off -line structures will likely have enough DA to make this <br />necessary. <br />