San Luis Valley: “Tale of Two Rivers” recap

Pond on the Garcia Ranch via Rio Grande Headwaters Land Trust

From The Valley Courier (Ruth Heide):

Hoping to avoid the wholesale shut down of agricultural wells in the San Luis Valley that occurred in the South Platte, water users here developed their own plan of action, Rio Grande Water Conservation District General Manager Cleave Simpson explained during “A Tale of Two Rivers” Monday night at Adams State.

Simpson spoke about the Rio Grande Basin’s groundwater journey while CSU Director of the Colorado Water Institute Reagan Waskom spoke about the South Platte Basin.

Attendees at the September 17 talk asked Simpson if local efforts were going to be enough, especially in light of drought and generally warmer conditions in recent years.

He responded that if voluntary efforts to reduce water consumption are not successful, the state will force the issue, because local water users — at least those in the basin’s first water management sub-district — are mandated to bring the aquifer levels back up to a certain level in a specified amount of time.

That clock is ticking, he said.

In its eighth year of operation Sub-District #1, sponsored by the water district Simpson manages, is required by legislation to bring the Rio Grande Basin’s aquifer up to a more sustainable level in 20 years, which means it has 12 years remaining on that mandate, Simpson explained.

The sub-district concept was born as a way to self govern water use in the basin, he said. The various sub-districts throughout the basin focus on “communities of interest,” Simpson said.

The first sub-district, which will soon have several sister sub-districts throughout the basin, covers about 3,000 irrigation wells involving about 300 landowners. They have used many methods to reduce their consumption, repair their wells’ injuries to surface water users and to meet their aquifer sustainability mandate, Simpson said.

He said the first sub-district has invested $8 million in fallowing projects and $6 million in acquiring and drying up parcels irrigated by groundwater…

He said, however, that speaking personally and not as the district manager, he believed a lot more acreage would need to be taken out. He said of the approximately 500,000 irrigated acres currently in the San Luis Valley, he believed 100,000-150,000 irrigated acres could no longer be supported with the dwindling water supply and aquifer sustainability mandate, unless farmers found a crop that used half the consumptive volume of water they are now using.

“There’s social consequences for taking 100,000 acres out of production in the Valley,” Simpson said.

Waskom added that the South Platte Basin is different in that it is not as agriculturally dependent as the Rio Grande Basin. While the Valley’s economy is still largely dependent on agriculture, the South Platte has more diversity such as oil/gas, growth and commercial enterprises. Losing cropland in the South Platte is not as crucial as it is in the San Luis Valley, he said.

“It’s different here. You need to think about that as a community, what your future looks like,” he said…

Simpson said that while groundwater users in the Rio Grande Basin must replace their injurious depletions to surface rights, just as in the South Platte, one major difference in the requirements between the two basins is the obligation in this basin to “create and maintain a sustainable aquifer … unique requirements … Nowhere else in the state are well owners held to that standard.”

That requirement must be met 20 years from the formation of the first sub-district, which is now eight years into that timeline, Simpson said. He added that while there is flexibility on how to get there, “where you have to get to is clearly well defined.”

He pointed to the downward trends in stream flows, specifically on the Rio Grande at the Del Norte gauge where for the first time since flows have been measured at that gauge (1890 forward), the river has gone 10 years without reaching the 700,000 acre-foot annual flow and about 20 years without hitting 800,000 acre feet. The annual flow this year is about 285,000 acre-feet.

Simpson added, “It’s probably not fair to call it a drought anymore. It’s climate. It’s just where we are, natural or man made, it’s just where we are at.”

Simpson also referred to the unconfined aquifer study the district has undertaken since 1976, which is generally the same area covered by the first sub-district. The aquifer remained fairly steady prior to 2002 and in that drought year alone lost 400,000 acre feet volume of water in that study area, Simpson said.

The first sub-district through its varied efforts of fallowing and conservation recovered about 350,000 acre feet, Simpson added. Experiencing three or four years of close to average flows helped. This year has presented more of a challenge, Simpson added, and he expected a decline in the aquifer storage area of about 200,000 acre feet.

San Luis Valley Groundwater

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