New dams found to be valid solution for water shortages

Soon after the Colorado Water Plan was approved in 2015, water users came together in unprecedented numbers to form roundtables and discuss approaches to meet each river basin’s forecasted water shortage.

On Tuesday, the South Platte River Opportunities Working Group, better known as SPROWG, presented its latest study on a possible solution — an intricate set of dams and pipelines that could increase the region’s yield by at least 50,000 acre-feet of water for municipal and industrial purposes, and 10,000 acre-feet for agriculture.

While municipalities such as Boulder and Longmont have secured enough water to meet their expected build-out — especially if the Windy Gap Firming Project is approved — for towns such as Frederick and Firestone, which continue to grow, this additional water will be vital to their survival.

“Colorado-Big Thompson water (which uses water from the Colorado River pumped over the Continental Divide to support communities along the Front Range) is nearly gone, and you can see that in the price,” said Ken Huson, Longmont’s water resource specialist who also serves as the Boulder County representative on the South Platte River Basin Roundtable. “It’s about $80,000 an acre-foot, so if that’s your plan, you’d better come up with a new one.”

The solution SPROWG came up with is a system of reservoirs and pipelines that could capture an estimated 300,000 acre-feet of South Platte River water that leaves Colorado each year above the amount needed to satisfy an interstate compact with Nebraska.

To accomplish this, the study presented Tuesday laid out four possible scenarios.

The first proposed creating three reservoirs; one with 25,000 acre-feet of storage near Balzac, one with 150,000-acre-feet near Kersey and one with 45,000 acrefeet near Henderson. Pipelines would also be installed to move water upstream and reuse it for meeting municipal demands.

The study estimated this configuration fully met future municipal demands in 64 of 69 years, and in those years at least 90% of the municipal demand was met. However, agricultural needs were met only 9% of the time in some areas because much of the water is forced to remain in the river for use in the Denver area.

The second option solved this issue by shifting 50,000 acre-feet of storage capacity from the reservoir near Kersey to the Balzac reservoir and installing a large pipeline directly connecting the Balzac reservoir to the Denver area. In doing so it increased the capability for water exchanges, resulting in agricultural needs being met in two of the basins’ three districts while reducing the overall diversion from the river by 5,000 acre-feet.

Using the same pipeline, the third option allowed for an additional 2,000 acre-feet of water to be delivered for agricultural use by adding a fourth reservoir with 8,000 acre-feet of storage near Julesburg. In doing so, it slightly increased the overall diversion as compared with the previous options, totaling to 223,000 acre-feet.

The study’s final scenario, which also incorporated the pipeline between Balzac and Denver, determined that higher projected water demands could be met while still providing an additional 3,000 acre-feet of water to agriculture if the overall storage capacity of all four reservoirs was doubled, allowing for more than 400,000-acre-feet to be taken from the South Platte River.