The applicant is requesting authorization to excavate and place fill material into Bois d’Arc Creek, a tributary of the Red River. The applicant proposes to construct the dam for the LBCR, which would allow the storage of about 367,609 acre-feet of water. The proposed reservoir would inundate several roads crossing Bois d’Arc Creek within the reservoir’s footprint. The realignment of FM 1396 and the construction of a new bridge over the reservoir would occur concurrently with dam construction and prior to impoundment of water within the reservoir. Also, associated with the LBCR would be a raw water intake pump station and electrical substation at the reservoir site, as well as a 90-to 96-inch diameter buried pipeline to transport raw water from the new reservoir approximately 35 miles in a southwesterly direction to a new water treatment plant (WTP) and terminal storage reservoir (TSR) that would be located west of the City of Leonard, also in Fannin County. Construction of the dam, reservoir, and related project components (road relocation, bridge construction, WTP, TSR, etc.) would take several years in all.
Construction of the reservoir and related facilities would result in direct, permanent impacts to approximately 6,180 acres of wetlands and 651,024 linear feet of streams. Approximately 4,602 acres of forested wetland would be impacted, 1,223 acres of emergent wetland, 49 acres of shrub wetland, and 87 acres of open waters.
At its full conservation elevation of 534 feet mean sea level (msl), the reservoir is expected to cover 16,641 acres and be approximately 70 feet deep at its deepest point. The dam would be constructed as a zoned earthen embankment; approximately 10,400 feet long and would have a maximum height of about 90 feet. The top elevation of the embankment would be 553.5 feet msl. The upstream slope of the embankment would be 3 horizontal to 1 vertical (3:1), and the downstream side slightly less inclined at a slope of 3.5:1. All fill for the embankment is expected to come from required excavations of the spillways and from the reservoir pool area. Soil cement would be placed on the upstream slope and a grass cover would be placed on the downstream slope.
Selected trees and shrubs would be cleared from the LBCR footprint prior to impoundment of water behind the dam. Standing woody material, including dead and living trees and shrubs 5 feet tall or taller, as well as fallen trees 5 feet or more in length with a diameter of 6 inches or greater, would be cleared and removed.
As noted, NTMWD would also construct raw water transmission facilities. These facilities would be part of an overall system of raw water storage, transmission, treatment, and treated water transmission facilities that would ultimately provide water to the growing northern areas of the NTMWDs service area. These proposed facilities include a raw water intake pump station and electrical substation at the reservoir site and approximately 35 miles of 90-to 96- inch diameter raw water pipeline.
The proposed raw water pipeline would generally run from just downstream of the proposed LBCR dam site in a southwesterly direction to just west of Leonard. The proposed pipeline would have a permanent easement width of 50 feet and a temporary easement width of 70 feet. Construction of the proposed pipeline would take place primarily with open-trench construction methods. However, three larger stream crossings (Ward, Honey Grove, and Bullard Creeks) would be tunneled. Once the pipeline is in place, all pre-construction contours would be restored, exposed slopes and streambanks would be stabilized, and disturbed areas would be revegetated.
The TSR is proposed for construction just west of the City of Leonard on an upland site. The TSR site would consist of a north cell and a south cell, with grading limits of approximately 153.5 acres. Both cells would hold approximately 210 million gallons of water, thus providing a total of approximately 2 days of storage during peak water demand periods. The TSR site would be designed in such a way that it can be drained and the flow directed into the Red River Basin.
Raw water transported from the proposed reservoir would be treated at a proposed WTP close to the TSR. The final WTP layout and processes would not be determined until the design phase of the LBCR project. The new WTP would likely be a conventional, modular arrangement treatment facility, similar to the existing WTP IV in Wylie, but with the addition of ozonation facilities. The LBCR Draft EIS can be be at the Tulsa Distict EIS webpage.