Many have been wondering why the U.S. Corps of Engineers is drawing down Sam Rayburn Lake in the midst of statewide drought conditions. Well, the fact of the matter is that although most of the state has experienced drought conditions, east Texas has not been hit as hard as other areas of Texas.
So, why is the Corps conducting a drawdown? Well, according to Sam Rayburn Lake manager, Reece Nelson, the drawdown is being conducted to make necessary repairs to replace riprap, a type of rocky armoring material used to protect shoreline structures against scour, wind and wave action, along the eastern portion of the Sam Rayburn dam.
“There has never been a managed drawdown or deviation from operating levels in the history of Sam Rayburn Reservoir operations, “says Nelson. “Although the dam is functioning as it was designed, risks to the structure will be increased if the work is not accomplished.”
This $13.2 million project is funded through a Rapid Disaster and Infrastructure contract and awarded to IE-Weston as the prime contractor, with opportunities for local sub-contractors within the east Texas area.
Much of the riprap armament on the lakeside of the dam is degraded, and continued exposure to high water events and wave action could lead to continued degradation of rock and surface of the dam structure.
“This work is being undertaken to maintain the long-term viability of the dam to meet stringent USACE standards and continued mission performance for dam safety and flood risk management,” Nelson added.
There are no anticipated road closures, as the contractor will build an access road on the slope of the dam to haul and place riprap. However, there will be additional traffic control on the east end of the dam to allow trucks safe access when turning off and coming back on to Sam Rayburn Parkway.
There will also be minimal impacts to recreation. Specifically, there will be no impact to access to Umphrey’s Pavilion or Twin Dikes Public Boat Ramp. However, the lowered lake levels will impact some ramps across the lake.
“The Sam Rayburn Lake office will continue pursuing options for minor dredging projects to allow these ramps to remain useable during the drawdown period, however at this time all means to pursue these actions have been unfeasible cost wise,” Nelson added.
The lake staff will also take advantage of the lowered lake levels to make repairs to boat ramp surfaces that have been compromised by high water and wave action.
One would think that there would be several environmental factors to consider when taking on something as serious as drawing down a lake, but this is not necessarily the case for the drawdown at this east Texas lake.
“With the size and depth of Sam Rayburn Lake, impacts to fisheries will be minimal,” added Nelson. “Under normal operations, as long as there is minimal elevation change during the spawning period, we see little to no effect to fisheries population. There is the potential for this year’s size class to be slightly smaller, but no long-term effects are expected to such a robust hatchery like Sam Rayburn.”
However, the Fort Worth District’s Natural Resource staff, in coordination with the State Historical Preservation Office, will conduct additional cultural resource surveillance on culturally sensitive areas that could be exposed due to the lower water levels.
“This includes additional routine and randomized patrols on locations of cultural significance that have had illegal looting in the past, and also additional spots where there have been surveys completed,” said Sam Rayburn lead ranger, Lynden Wood.
Aside from making necessary repairs, there are other positive aspects of the drawdown. For example, the lower controlled elevation will allow for natural revegetation of the shoreline, which in turn will increase fish habitat and then fishery population once the lake level rises again.
However, during these lower lake levels, boaters should be aware of additional underwater structures, stumps, logs and sandbars which may be exposed. Corps officials caution boaters to be cognizant of these changes and prepare accordingly.
When navigating Sam Rayburn while the lake level is higher or lower than conservation pool, fishing graphs can only tell you so much, so we urge boaters and passengers to make sure they are aware of their surroundings,” said Emily LaPerriere, a Sam Rayburn park ranger. “Use your graphs, but visually see where you are going and use a spotter if necessary to stay on the right path. And always wear your lifejacket.”
Final details on the project are still being ironed out so the start dates for both the drawdown and project initiation are unavailable, but Corps officials are hopeful the project will be wrapping up by fall of next year.
“The majority of the project is expected to be completed by late spring to early summer of 2024 and during the construction period, the lake will be managed to stay around the 158-feet mean sea level elevation range, which is within the regular pool fluctuation for Sam Rayburn” stated Nelson.