SOUTH PLATTE STORAGE STUDY & COLORADO WATER PLAN UPDATE Gmda summer 2018 Savannah, GA Randy Ray - ccwcd

Lots going on in Colorado from a water standpoint, like most western states. Irrigation, municipal needs, environmental and recreational users want to ensure adequate water supply now and into the future.

South platte basin survey (500) 500 people surveyed who participated in the development of the water plan – here’s where priorities fall out. I’m not sure the data wouldn’t look the same back in 1950… Many call Colorado their playground and values for water supplies have shifted as the front range as well as western slope needs – from skiing to fishing to maintenance of minimum stream-flows for aquatic benefits. West slope agriculture plays a big key to the state economy, even though 80% of the state’s income resides on the east side of the hill.

Show the South Platte River with the pointer Show the South Platte River with the pointer. Assumes 70% success rate for the IPP’s (identified projects & processes). Sum of net gap by 2050 = 196,000 AF, 400,000 acres of irrigated farms – high end, 230,000 acres if IPP’s are successful. 45,500 AF of shortage is identified in Weld County – ranks 4th in the nation for ag production.

IPP’s – South platte (not all, but the large) Chatfield reallocation project (20,600 AF) ag & Muni Moffat firming, gross reservoir (400,000 AF) Denver water Milton/seaman reservoir expansion (30,000 AF) city of Greeley Nisp (157,000 AF) Northern water, multiple northern Colorado muni’s Windy Gap firming/Chimney hollow - northern water, multiple northern Colorado muni’s Prairie waters - city of aurora & muni partners Reuse projects by metro muni’s (gravel pits/exchanges) Asr – Denver basin aquifer muni’s Buy & dry (requires rights of exchange and necessary storage) ATM’s (use ag water in dry years) Conservation (muni’s, but pressure on ag) What are these IPP’s? Will highlight a few and give more details to some in upcoming slides. We have new reservoirs, expansion of existing reservoirs, alluvial recharge, confined aquifer storage, buy & dry still going on. Conservation plays a role in municipal demans in the future. New developments using dual water systems, higher density housing drives down per capita water needs. Denver used the same amount of water last year as in the 1970’s – conservation working there. Irrigated ag conservation isn’t the entire answer – irrigation return flows feed the river for other downstream users. ATM’s have been the buzz for several years. Alternative Transfer Mechanisms – the goal of this concept is for ag to share with the city cousins in dry years. Works much better in other basins in Colorado such as the Arkansas with the benefit of Pueblo Reservoir. The south platte needs large storage buckets to make it work here.

Who’s go the $$$$ Denver Metro Area - down river – Senior Water $20,000/AF Central South Platte Region – Senior Water $15,000/AF Lower River (last 100 miles to Stateline) $5,000/AF Costs are not inclusive of infrastructure Water Court pumping costs Conveyance to municipal use. The senior water right market is ruled just like real-estate. Value is based on “location, location, location”. Pre-2002 drought, Central purchased senior water at $5,000/AF – now $20,000. CBT (Colorado big Thompson) at that time $7,500/AF – today $30,000. There are transaction costs which escalate the further down-river from Denver they go. Pipelines, pumpstations, water treatment, costs go up dramatically, doesn’t always pencil out. Furthest downstream rediversion is Aurora’s Prairie Waters project, located near Brighton (about 25 miles downstream of downtown Denver). The project pumps water around the eastern edge of Denver to water treatment plant of Aurora’s. To expand on that conveyance project, Auora and Denver Water has teamed up to provide cash and water to extend that pipeline all the way around to the southern end of Denver to supply water customers such as Castle Rock (some 60+miles of pipeline)– reusable water released and treated from the major water treatment plants in Denver. The origin of the water is reusable effluent, which was diverted from the western slope and used the first time by Denver Water customers. Accounting nightmare, keeps the engineers and attorneys fed.

Permitting new supplies Chatfield Reservoir – Municipal & Agricultural, 20,600 AF of new storage space. 1975 construction by USACE (350,000 AF) 1983 appropriation date by Central. 1986 WRTA Bill in Congress authorized work. 1997 congress – reconnaissance study - $100,000 2005-2013 no $ in presidents budget – lobby efforts and state matching ($) with project members 2012 draft Fr/eis 2013 FR/EIS, 2014 ROD 2016 construction commences, 2020 water storage Windy gap firming – chimney hollow reservoir 1985 windy gap project completed 2003 – 13 water providers initiate federal permitting with USBR 2008 – usbr d-eis 2014 – usbr issues rod 2017 – usace issues rod 2019 – construction of asphalt-core dam to commence 23 years for Chatfield (from the 1997 approval for congressional funding to 2020). Keep in mind, 2005 the project would have been dead without project participant efforts and support from State of Colorado. Chimney Hollow - 14 years from draft EIS to estimated construction completion.

South platte storage study Shifting gears to the storage study, supported and legislatively led by west slope representative Brown. Bill had objectives, 1) how much flows to Nebraska, 2) where to site on-stream, where to site off-stream reservoirs, 3) evaluate aquifer storage, 4) price the storage in $/AF.

Where’s the water? Kersey area, location downstream of four major tributaries to the S. Platte. Brush, only downstream obligation – NE compact, and non-compact times only obligation is Julesburg reservoir – lots of excess recharge accretions. Where’s the demand? Where’s the money? Denver burbs. Show pipelines, explain the exchanges using gravel storage. Explain the challenges with irrigation season and winter reservoir dry-up points on the river. Talk some to water quality diminishing downstream – challenges for water treatment.

West slope supply to eastern slope? 80% of population on east slope West Slope – “not one more damn drop” Several years – lower than average snowpack Lower basin states over allocation Upper basin states – Lake Powell as the “buffer” Pre-Compact rights on the western slope For years, east slope demands met with west slope water. Dwindling snowpack in years like this year. Allocations to the states based on wet year hydrology – assumed too much water to be had by all.

west slope reaction to south platte storage study Eric Kuhn, governor's appointee to the IBCC: “West Slope might want to see some protections that these reservoirs don't end up sitting there empty for a long time and that it doesn't just drag additional transmountain water over the hill."

Ccwcd projects our water plan 80,000 AF – sum of contracts for annual supply 67,000 AF – pumping allocation in 2018 (55% quota) 12,500 AF – lined gravel storage 4,300 AF – senior water rights 17,500 AF – leased municipal supply 13,200 AF – recharge diversions in 2017

Ccwcd projects our water plan 4,300 AF – new gravel storage online in 2018 Negotiation with Denver water – firm 1,300 af annually Robert w. walker recharge project 50 cfs diversion – well field 50 cfs diversion – surface 30,000 af annual maximum

Walker Recharge Project - Phase 1   Desc. Quantity Cost Wells/Pumps/Manifold/Controls 6 $3,193,750 36" Mainline 7,900 $2,269,000 10 acre recharge basin $176,000 Surface diversion/10 Ac recharge basin $266,500 Engineering/Permitting/Contingency $1,800,000 subtotal $7,705,250 Walker Recharge Project - Phase 2 $3,200,000 36" & 24" Pipeline 32,000 10 recharge basins (size varies) $1,500,000 Surface diversion & River Crossing $2,500,000 $11,269,000 Walker Recharge Project - Project Total $18,974,250 Annual Yield = 12,000 AF/YR Capital Cost per AF $1,581 2016, Central purchased 226 acres of riverbottom at auction. December 2016, filed water court application, June 1 2018 draft decree & engineering report due. $1.5M in State and Federal grants (Colo Water Plan, USBR). Three years to complete Phase 1 per USBR grant. Numerous project partners, local CCWCD water allotment contract members (will get addtioinal pumping), Town of Wiggins, needs help with growth and their augmentation plan, irrigation companies in the area – attraction is the size, and distance from the river to provide long term recharge accretions to the river – covers projection periods to bridge dry years when junior water rights such as this are out of priority. Nearby CCWCD project, cost/AF for power for 100 HP motors and 40’ of lift is $8/AF. Estimated cost for Walker wells is $12/AF – based on 250 HP submersible pumps with 90’ of vertical head. Wells pumping from aquifer formation about 80’ of depth with 75’ of saturated thickness. The project will help all 80,000 acres irrigated by CCWCD members, and in particular this location where nearly all these farms use groundwater as their only source of water. Three large dairy operations located here, about 12,000 cows.