News

Flood control dam to be upgraded

One of four flood control dams along the Lower Running Water Draw, TX watershed and the closest structure to Plainview, TX is in line for almost $3.3 million in upgrades. The dam, which is listed as No. 4, is located about 2 1/2 miles west of Plainview along 24th Street. It is on the Slaton Draw which flows into the Running Water Draw, and is immediately north of the Pleasant Hills Addition. Two other dams are on the main channel in Hale County, in extreme northwest Hale County and just west of the Runningwater School site. Another dam is located outside Hart. Three other dams, further upstream starting in Clovis, N.M., make up the Upper Running Water Draw portion of the project. City Manager Jeffrey Snyder reported on a recent public hearing on the project to the city council at its work session on Thursday. It was the second public hearing held by USDA’s Natural Resources Conservation Service (former Soil Conservation Service).

 

Actual funding for the upgrades could be several years ago, Snyder noted. Total project cost has been set at $4,008,500, including $631,600 for NRCS engineering and $81,000 for project administration. The remaining $3,295,900 is eligible for a 65/35 percent match, with the NRCS share set at $2,142,300 and the sponsor share (35 percent) at $1,153,600. Of that total, the Texas Soil and Water Conservation Board is expected to fund 95 percent, leaving about $58,000 for the local sponsors – the City of Plainview, Hale County and the Hale Council Soil and Water Conservation District.

 

Snyder noted that the flood control project along the draw, was first proposed following a 100-year flood event in Plainview in 1960 and a second major flood in 1965. Planning began in 1968 and construction of the No. 4 site was completed in 1976. Built as a significant hazard dam, the No. 4 was reclassified as a high hazard dam in 2008 following a breach analysis. That change in status came after the realization of significant construction within the flood zone below the dam site. The analysis looked at the possible consequences if structure failure:

--Total population at risk (onsite): 446

--Properties at risk: 66 residences, 58 commercial, 12 public

--Roads/crossings that would flood: I-27, Business I-27, US-70, FM 400 (Date Street), numerous city streets, several county roads

--Park areas and golf course along draw would flood.

--1,932 total acres flooded (1,551 acres of agricultural land and 381 acres of urban area)

--Monetary damages of $12 million (urban areas $12 million, road crossings $2.3 million, ag land $700,000)

The proposed rehabilitation includes:

--Install 340 foot wide roller compacted concrete auxiliary spillway over embankment

--Existing 30-inch conduit remains in place and will empty into the RCC stilling basin.

--Lower top of dam crest elevation 0.1 feet.

--Re-grade upstream slope of dam to original slope dimensions and flatten downstream slope to 3:1.

--Ensure a minimum additional 100-years sediment capacity is provided.

--Ensure that an adequate Emergency Action Plan is developed.

Snyder reported that all three local sponsors have submitted recent letters showing their continued support of the project. The actual timing of the project, he notes, is dependent on its priority ranking along with funding availability.

Thanks Ron