CWCB: May 2016 Drought Update

From the Colorado Water Conservation Board (Tracy Kosloff):

Cooler than average temperatures & wet conditions across most of Colorado has eliminated most D0, abnormally dry, conditions since late April. Only 3.8% of the state is currently experiencing D0 conditions. Recent storms improved snowpack in the central mountains and have brought much needed moisture to the Southwest basins. The forecast over the next two weeks shows continued cool temperatures and more chances for precipitation. The long term CPC forecast predicts a wet and cool first half of the summer changing to warm and dry conditions going into the fall.

  • Statewide water year to-date precipitation as reported from NRCS is at 137% of average as of May 25, with the west slope benefiting from late April & May storms receiving up to 4 inches in certain areas.
  • Reservoir storage statewide remains above normal at 112%. The Arkansas basin has the highest storage levels in the state at 118% of average; the Upper Rio Grande has the lowest storage levels at 91%, just slightly below normal although the basin has been steadily improving since 2013.
  • The Surface Water Supply Index (SWSI) as of May 25th is near or above average across the majority of the state. At this time of year the index reflects reservoir storage and streamflow forecasts. May storms have helped increase SWSI values in the Southwest & Rio Grande basins.
  • May 1st streamflow forecasts are near normal to above normal in the northern half of the state and mostly below average in the southern half of the state. Due to May storms that have benefited the Southwest basin, the June 1 streamflow forecast should see more improvement.
  • Agricultural producers are experiencing a decent year so far benefiting from lower temperatures and higher humidity from statewide storms. Corn & bean planting is slightly below average at this time of year.
  • Upper Colorado River Basin May 2015 precipitation as a percent of normal
    Upper Colorado River Basin May 2015 precipitation as a percent of normal

    From The Pueblo Chieftain (Chris Woodka):

    …a year after “Miracle May,” the Arkansas Valley has left Cloud 9, and again will settle for a Cloud 5 or 6 and hopefully not plunge to earth again. Rainfall and snowpack are looking good this year, both still above average. More waves of rain or snow keep arriving every other week or so.

    But over the long term, the basin still is catching up when it comes to water storage. A graph, presented by the Natural Resources Conservation Service at April’s state drought task force meeting, shows that overall storage poked its nose above average along the Arkansas River only twice in 15 years. Two multi-year droughts and a decline in usable storage space were to blame.

    Spoiled in the ’90s

    The wet years from 1995-99 created the largest surplus of stored water yet observed in the Arkansas River basin. At times, there more than 600,000 acre-feet — enough to supply Pueblo’s basic needs for 20 years — in storage.

    The decade was a great time for optimism all along the Arkansas River.

    In the upper reaches a new state recreation area was getting off the ground and the rafting industry, bolstered by a voluntary agreement to keep water in the river during early summer, was growing.

    Kiowa County pushed hard to create a state park around the Great Plains reservoirs that are usually empty.

    The Southeastern Colorado Water Conservancy District was drawing up plans to study where to put even more water, after the state fended off challenges by Kansas over increased storage in Lake Pueblo and Trinidad Lake.

    The Bureau of Reclamation bolstered Pueblo Dam, for safety reasons and for the possibility of enlarging the storage space behind it. There was so much water that some of it was released intentionally in order to fortify the concrete center portion of the dam.

    Crash of 2000s

    But Mother Nature turned off the spigot in 2000, acting much like a homeowner who decides to just let the lawn die. There was a swing of 1 million acre-feet, from 750,000 acre-feet above average to 250,000 acre-feet below in just three years. On top of that, in 2005, the U.S. Geological Survey determined there was also a soil moisture deficit of 1 million acre-feet over the same time span.

    The tone of water discussions changed dramatically, beginning in 2002.

    Those arguing for increased storage said building more storage would ease the pain and allow water users to survive the swings in drought. Colorado Springs, Aurora and Pueblo put in water restrictions in 2002. Aurora, which fought for and won storage space as an outsider, made its restrictions permanent and built its Prairie Waters system to reuse its water from other basins.

    But others weren’t sure the increased storage would just take more water from agriculture to fuel urban growth.

    Voters in five counties formed the Lower Arkansas Valley Water Conservancy District for the purpose of preventing the cities from grabbing even more water, as Aurora was doing by buying up most of the remaining shares of the Rocky Ford Ditch it had left behind in the 1980s.

    The sense of urgency diminished, PSOP led to a battle royale between, at times, 11 entities that ended in a draw in 2007.

    Water planners faced the prospect of a refill of reservoirs that would take years, and dove into a statewide discussion, through basin roundtables and the Interbasin Compact Committee, about how to conserve, share and build Colorado out of a drought.

    Other factors

    At the same time, the Arkansas River basin continued to lose storage.

    Some reservoirs have been put under restrictions for dam safety reasons and are expensive and difficult to renovate. Colorado Parks and Recreation is renovating Two Buttes Reservoir south of Lamar, while a private developer has a plan to rebuild Cucharas Reservoir southeast of Pueblo.

    Others have been restricted for insufficient water rights, such as Lance Verhoeff’s small reservoirs that serve as bird and wildlife preserves on private land near McClave. Finding water to store in the reservoirs has been problematic. In Pueblo, Lake Minnequa was made into a city park, but required intervention by Pueblo Water and the Lower Ark district to retain water during dry years.

    Finally, all reservoirs eventually lose capacity because of silt. Capacity at Lake Pueblo, for instance was downgraded last year after a study showed where sediment has filled areas on the lake bed.

    New dams?

    Yet, there is the possibility that more dams could be built in the future.

    Several projects are already on the drawing board. They are expensive, however, and take years of planning.

    Excavation already is already underway at Stonewall Springs east of Pueblo, a site that could be used for recovery storage by cities, wildlife or downstream supply.

    The Fountain Creek Watershed Flood Control and Greenway District is looking at the possibility of a flood control dam on Fountain Creek. It’s not envisioned as a primary storage project, but some models have incorporated storage.

    Colorado Springs Utilities has plans for two dams on Williams Creek, a tributary of Fountain Creek located south of the city, one for terminal storage for Southern Delivery System and the other to regulate return flows.

    Pueblo Water has plans to more than double the size of Clear Creek Reservoir, south of Leadville.

    Just one hurdle to overcome: Where to find the water to fill them?

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