Albuquerque District Arkansas San Juan Canadian nisaB ednarG oiR ednarG nisaB Rio Grande Platoro COLORADO Pecos Heron El Vado Abiquiu Jemez Canyon Cochiti Galisteo 40 25 Elephant Butte Caballo 10 NEW MEXICO TEXAS 2020 Water Management and Civil Works Report This page intentionally left blank. Table of Contents 1. General ...................................................................................................................... 1 2. Water Management Operations.................................................................................. 1 A. Snow Melt and River Flows .................................................................................... 1 B. Flood Risk Management Operations ...................................................................... 2 C. Non-Flood Risk Management Operations .............................................................. 5 D. Other Activities at Dams and Reservoirs ................................................................ 5 E. Power Generation ................................................................................................... 7 3. Civil Works Authorities and Programs ........................................................................ 8 A. New Mexico Investigation Studies .......................................................................... 8 B. New Mexico Construction Activities ........................................................................ 9 C. Texas Investigation Studies .................................................................................. 13 D. Texas Construction Projects ................................................................................. 13 E. Multi-State Studies ............................................................................................... 14 4. Regulatory Program (Section 404 of the Clean Water Act) ....................................... 14 5. Other Programs ........................................................................................................ 15 A. Upper Rio Grande Water Operations Model ......................................................... 15 B. Middle Rio Grande Endangered Species Collaborative Program ......................... 16 6. Flood Plain Management Services Program ............................................................ 17 7. Flood Risk Management Program ............................................................................ 18 8. Emergency Management Coordination .................................................................... 20 1. General During calendar year 2020, the U.S. Army Corps of Engineers (USACE), Albuquerque District, undertook a wide range of activities in the Rio Grande Basin. These activities consisted of routine reservoir regulation and monitoring of streamflow conditions; flood risk management studies; ecosystem restoration, design and construction; operation and maintenance of flood risk management structures; planning assistance; floodplain management services; emergency rehabilitation assistance; and the regulation of dredged or fill materials into waterways. 2. Water Management Operations This section characterizes river flows in 2020 and describes USACE actions to manage flood flows throughout the year. A. Snow Melt and River Flows In 2020, the Rio Grande Basin snowmelt runoff forecast was well below average throughout the basin, at about 65 percent of average in early March. By May 1st, the Upper Rio Grande Basin in Colorado dropped to about 60 percent of average and in New Mexico to about 36 percent of average. Table 1 compares the Natural Resources Conservation Service’s (NRCS) forecast runoff to the actual measured runoff, ordered from north to south within the Rio Grande watershed. Table 1: May 1, 2020, NRCS Forecast and Actual Runoff st Rio Grande Basin May 1 Most Probable Snowmelt Runoff Forecast (50% Exceedance) Forecast Percent of Actual Snowmelt Percent of Location Snowmelt Runoff Average Runoff (x 1,000 Average (x 1,000 acre-feet) acre-feet) Rio Grande at Del Norte 320 62 309 60 (Apr-Sep) Platoro Reservoir Inflow 37 60 41 66 (Apr-Sep) Conejos River at Mogote 105 54 114 59 (Apr-Sep) El Vado Reservoir Inflow 81 36 82 36 (Mar-Jul) Rio Grande at Otowi 260 36 264 37 (Mar-Jul) Jemez Canyon Reservoir 13.1 39 9.3 27 Inflow (Mar-Jul) 1 The actual Rio Grande Basin snowmelt runoff ranged from 27 to 66 percent of average producing well below average water supply conditions. With the exception of Jemez Canyon Reservoir inflow, the actual spring runoff volumes measured at most forecast points was very close to the May 1st NRCS spring runoff forecasts as shown in Table 1. The below average spring runoff experienced in the Upper Rio Grande Basin of Colorado resulted in a total spring runoff volume of approximately 55,200 acre-feet arriving at the CO-NM state line, which is about 25 percent of average. The March through July spring runoff for the Rio Chama upstream of El Vado Dam totaled approximately 82,000 acre- feet, or about 36 percent of average. For the same time period, the total volume of native Rio Grande water (natural unregulated flow) at the Otowi, New Mexico gage was approximately 264,000 acre-feet, which is about 37 percent of average. B. Flood Risk Management Operations Abiquiu Reservoir began the year with approximately 82,000 acre-feet in storage, peaking at 92,386 acre-feet on 12 May 2020 and ending the year with 66,400 acre-feet. All water stored in Abiquiu reservoir is San Juan Chama water, and no native Rio Grande flood water was stored during 2020. With well below average spring runoff in the Rio Chama Basin, and no large summer storms to note, USACE did not engage in any flood operations in 2020. However, USACE remained engaged in external coordination activities with stakeholders up and down the Rio Chama from El Vado Reservoir to Española, New Mexico. Figure 1: 2020 Abiquiu Dam and Reservoir Water Operations 2 Cochiti Lake’s recreation pool (San Juan-Chama water) began the year with approximately 42,200 acre-feet, peaking at 46,500 acre-feet on 22 March 2020, and ending the year with 42,400 acre-feet in storage. Flow at the Otowi gage, upstream of Cochiti Lake, averaged about 710 cfs during January and February, 925 cfs during the spring runoff period (March through July) and about 530 cfs for the rest of the year. Releases out of Cochiti were set to closely match inflows, averaging approximately 880 cfs during the spring runoff period and reaching the spring runoff peak releases of about 1,000 cfs from May through the end of June. Downstream of Cochiti Dam, the flow at the Albuquerque gage averaged about 550 cfs from January to mid-July, while the remainder of the year saw an average of about 270 cfs. Figure 2 illustrates 2020 water operations at Cochiti Dam and Lake. Cochiti Lake 47,000 2,000 46,000 1,750 45,000 1,500 feet) - 44,000 1,250 43,000 1,000 42,000 750 41,000 500 Lake Storage (acre Storage Lake 40,000 250 (cfs) and Release Inflow Computed 39,000 0 Lake Storage Computed Inflow Release Figure 2: 2020 Cochiti Dam and Lake Operations Jemez Canyon Reservoir is operated as dry reservoir and all inflows are passed unregulated through the dam up to the downstream channel capacity. The inflow averaged approximately 60 cfs from March to about mid-May with a maximum of about 135 cfs. Reservoir outflow matched inflow and there was no storage accumulation during 2020, as shown in Figure 3. 3 Jemez Canyon Dam and Reservoir 10 200 9 180 8 160 7 140 feet) - 6 120 5 100 4 80 3 60 Lake Storage (acre Storage Lake 2 40 1 20 (cfs) and Release Inflow Computed 0 0 Lake Storage Computed Inflow Release Figure 3: 2020 Jemez Canyon Dam and Reservoir Water Operations Galisteo Reservoir received inflow during the 2020 runoff season that peaked at about 80 cfs. During 2020, the outflow matched the inflow with no storage as shown in Figure 4. Galisteo Dam and Reservoir 10 100 9 90 8 80 7 70 feet) - 6 60 5 50 4 40 3 30 Lake Storage (acre Storage Lake 2 20 1 10 (cfs) and Release Inflow Computed 0 0 Lake Storage Computed Inflow Release Figure 4: 2020 Galisteo Dam and Reservoir Water Operations During 2020, there was no flood operations at any of USACE dams in the Rio Grande Basin. USACE remained engaged in external coordination activities with stakeholders 4 up and down the Rio Grande from Alamosa, Colorado, to Elephant Butte Dam and Lake, New Mexico. C. Non-Flood Risk Management Operations Non-flood water control operations include activities such as emergency deviations to facilitate search and rescue, and other activities that temporarily alter flow from dams, lakes, and reservoirs along the Rio Grande. During 2020, non-flood operations were limited to short-term reductions in the release rate at Abiquiu to complete required maintenance activities on the conduit vent pipes, and short-term reductions in the release rate at Cochiti to allow for inspections of Cochiti’s outlet works and to install andremove fish screens on the irrigation works intake structure. All these short-term flow reductions were scheduled to minimize the disruption to downstream water users, and they lasted no more than one to five hours in duration. D. Other Activities at Dams and Reservoirs i. Abiquiu Dam and Lake a. Rio Chama Aquatic Habitat Improvement Project This project aims to improve the overall riparian habitat, instream conditions, and recreational opportunities on the Rio Chama below Abiquiu Dam. The instream aquatic habitat features for trout and other fish species were designed by Riverbend Engineering based on techniques