Bennett Raley, Interior’s Assistant Secretary for Water and Science, joined Socorro Mayor Baskar Ravi in congratulating Subhas Shah, Middle Rio Grande Conservancy District (MRGCD), on the automation of San Acacia gates during the dedication ceremony on May 27. Reclamation’s Albuquerque Area Office (AAO) and MRGCD had discussed gate automation for several years, since water management for Endangered Species Act (ESA) requirements has become critical.
The San Acacia Diversion Dam sits upstream of a reach on the Rio Grande that experiences significant fluctuations in flow caused by diversions and depletions as well as natural diurnal variations in riparian depletions. The location, highly variable flows and manual operations required at the diversion dam were causing serious problems related to management of flows for the ESA biological opinion targets. Gate adjustments were often required in the middle of the night and on weekends. Failing to keep minimum flows in the Rio Grande could result in non-compliance with biological opinion target flows for the endangered Rio Grande silvery minnow.
Gate automation allows MRGCD to make time-critical gate adjustments remotely from Albuquerque very quickly, no matter the time of day, and it also improves MRGCD’s efficiency for water delivery in its Socorro Division.
MRGCD had completed gate automation at other strategic locations during the past several years and realized its benefits. In the Fall of 2003, MRGCD asked the AAO for assistance in getting the gates automated at San Acacia Diversion Dam prior to the start of the 2004 irrigation season. MRGCD was ready to fund and construct the automated gate modifications and asked the AAO for assistance in design and required environmental and cultural resources clearance. The AAO and MRGCD worked closely together to accomplish this work over the winter and early spring months.
A unique feature of the new concrete wall and sills was that the rebar was not doweled into the existing gate bay piers or floor, since this required a long rebar embedment length. Metal angles were attached to the concrete piers using anchor bolts. The motorized radial gate drum assembly was designed to be mounted under the existing bridge deck so as not to limit the use of the existing lift mechanism for opening and closing all of the other radial gates. Each of these design considerations helped to avoid adverse affects to the existing structure, which is considered an historic property.
At the dedication, Raley commented on how helpful the new gates would be in water management and that such a project was exactly the kind of project Interior Secretary Norton was anticipating through the Water 2025 initiative.
After the ceremony, staff from MRGCD took Raley to a couple of other “problem areas” that they hope to address with Water 2025 funds.