South Platte Roundtable: More urgent water planning needed; conservation complicated for basin
LONGMONT – More urgency is needed when it comes to planning new water-supply projects, and water conservation isn’t the silver bullet to solve future shortages in the South Platte River Basin, where reused water is an essential supply source downstream.
Those were two focal points of discussions at the four-hour South Platte Basin Roundtable meeting Tuesday night.
Roundtable members, made up of water experts and officials in northeastern Colorado, stressed during their meeting that – because it takes water-supply projects, such as new reservoirs, 20-30 years to come to fruition, from the planning stages to their completion – the expected shortfalls in the South Platte’s water availability could arrive before enough new projects can come to fruition.
That is, unless much more aggressive planning among regional and state water officials begins to take place soon, members agreed.
The Statewide Water Supply Initiative study, compiled by the Colorado Water Conservation Board, estimates the South Platte River Basin will face a water-supply gap of between 36,000 and 170,000 acre-feet by 2050. One acre-foot of water serves 21/2 families of four for one year, while an acre of corn requires somewhere around 1.5 acre-feet of supplemental irrigation per year.
The South Platte Roundtable is one of nine roundtables in the state – one representing each of the eight river basins in the state and one representing the Denver metro area. The roundtables convene monthly to discuss plans and ideas for solving the water-supply gap that’s expected because of the state’s rapid population growth.
South Platte Roundtable members also made note of the ongoing push from others in the state – particularly those from the Western Slope – to heavily rely on conservation efforts to meeting future water needs, rather than depend on building new projects that transport water from the Western Slope to the Front Range.
Roundtable members pointed out that conservation is complicated in the South Platte, because so many of its users depend on reused water. They noted that many other people in the state don’t fully understand that, and more education is needed.
Unlike other basins in the state, water in the South Platte Basin is reused six or seven times before it flows out of the state. South Platte water users, particularly those east of Greeley and further downstream, are dependant on water that’s used in the Denver area and other parts of the upper South Platte region, treated before it returns to the river and then flows downstream to be used again.
It’s estimated that about 50 percent of the water used by farmers in flood irrigating returns to the river – either by soaking through the soil and into underground aquifers, or through ditch runoff. About 18 percent of water used in residential lawn irrigating is estimated to return to the river.
With its reuse system in place, the South Platte Basin’s economic value per acre-foot of water is higher than any other basin in the state.
Conservation efforts put in place during the past 10 years have been “very helpful” in reducing per capita water along the Front Range. However, if upstream water users begin using less water through added conservation efforts, it would complicate the South Platte Basin’s efficient water-reuse system, they added.
Because the Poudre River is the last major tributary stream along the South Platte River – flowing into the South Platte just a few miles east of Greeley – reused water is a critical supply source to municipalities and farmers to the east.