KRWG

Las Cruces-Area Flood Awareness And Planning

Sep 11, 2017

Stormwater entering from the watersheds has a great impact on the entire region here in the Elephant Butte Irrigation District. Harnessing this additional supply of water can minimize flooding, recharge the aquifers and provide other irrigation and economic benefits. However, stormwater management must begin at the top of the watersheds to reduce the volume, settle out sedimentation and control the velocity of the water before it reaches populated areas along the river. EBID Manager Gary Esslinger says it is critical “to build sound science infrastructure to capture and salvage this precious resource before it becomes a public safety and welfare nightmare for the unsuspecting residents in the valley floor.”

Historically, “The Rio Grande was essentially a stormwater stream, subject to great and sudden floods or becoming a dry stream bed because of severe drought,” Esslinger notes, “The region’s rainfall occurs principally in the form of intense “Cloud Bursts” during the monsoon season, which fill the dry ephemeral streams/arroyos with turbulent, sediment loaded stormwater for short durations. When those storms occur simultaneously in many parts of the region they cause destructive floods in other parts of the valley, as evident of the Hatch flooding in 2006.”

The “feast or famine” nature of the river flow changed upon the completion of Elephant Butte and Caballo Dams 100 miles upstream in 1916 and 1933 respectively, enabling the capture and storage of snow melt run off from the southern Rockies. However, even today irrigated agricultural land, communities and cities along the river course are often inundated with flood debris and submerged roads and highways add enormous high costs to the property damage.

Available funding has been inadequate and sporadic to take on the noble effort of maintaining these dams at a standard to protect the public safety and welfare. The City of Las Cruces, Dona Ana County, other public entities and farmers have tried to address this concern within their limits.

Hundreds of flood dams up and down the East and West mesas, public and private, exist today.

EBID sponsors 27 of these flood structures in the Rincon and Mesilla Valleys because the stormwater outflow from these dams flows directly into our canals and laterals rather than directly to the river. Flooding can result further downstream from where the initial mishap occurred due to the fact that our canal system now carries flood water downstream to areas which otherwise may not have been susceptible to flooding. Unfortunately, a vast majority of the watersheds that remain are uncontrolled arroyos and gullies that directly impact the escarpments and valley floor. As Houston experienced, when additional rainfall falls on already saturated ground and full waterways, flooding is inevitable. Future flood flows in our own narrow valley are a very real possibility in the event of a major storm and have the potential to impact us catastrophically.

Esslinger says, “I have been accused of being a fear monger but this valley is in the cross hairs of a horrific flood event. It is time for serious objective planning that begins to focus and recognize the benefit of addressing water matters at the base of the mountains and upper watersheds rather than at the valley entrance. We must look at the entire watersheds, alluviums and an enormous area of connecting arroyos and gullies as part of the system to be managed and protected.”

Regional planning must not ignore the potential loss of property and economic devastation from flooding. If a 100 year storm event hits our local region, will we be prepared? It is not “if” it will happen, but “when.” Esslinger cautions, “We can no longer afford to live in the “land of mañana.”

Information from EBID