Water Development
How? This water replacement strategy is based on the construction of a new reservoir on the San Bernard River near Boling to replace the water transferred to Williamson County. The reservoir would capture stream flow and make it available for irrigation. A pump station and pipeline would transport the water from the reservoir to the irrigation districts.
How Much? The San Bernard reservoir is expected to yield about 30,000 acre-feet of water when all senior water rights are honored. It would capture about 50,000 acre-feet per year and have a surface area of 5,000 acres.
Is it Scaleable? Generally, the reservoir and water transfer facilities would need to be built at the full capacity of the system. Some elements may initially be sized for a smaller capacity. For example, pipelines to some irrigation areas could initially be constructed with others added at a later time.
Comparability Criteria
Costs? If the cost were comparable to one to two off-channel reservoirs, as envisioned in the Regional Water Supply Plan, and pumping and pipeline costs are added , the initial cost would be approximately $90 million. Annual costs to operate pumping and pipeline systems needed to transport the water to the irrigation districts are estimated at $50 per acre-foot. Detailed studies of this strategy have not been performed and the costs are difficult to estimate without that information. These estimates should be viewed as very preliminary.
Benefits? Significant deep water habitat would be developed, and the wetlands in the rice areas would be sustained by the availability of water.
Sustainability? This alternative is sustainable, assuming that upstream erosion and sediment accumulation in the reservoir do not significantly reduce its long-term storage capacity.
Reliability? The reliability of this reservoir is based on firm yield principles, which take into account the drought of record. Therefore, the expected firm yield would be reliable.
Risk? Obtaining the necessary permits may be difficult. Land for the reservoir must be purchased or condemned. During implementation the pump station will need to be managed in connection with the other irrigation system facilities, making system management more complex.
Permit Requirements? A permit for storage and diversion of “waters of the state” is required. This is sometimes difficult to obtain if the other surface water permit holders in the basin oppose the permit, or if there is significant environmental or recreational opposition. Section 404 and Section 10 permits from the Corps of Engineers are also required. These permits require a variety of environmental issues to be addressed, including: wetland impacts, habitat impacts, water requirements, and other environmental issues. Pipeline rights-of-way must be obtained.
Implementation Time? Minimum time to implement could be 7 to 10 years. Planning, environmental studies, and permitting alone could require 5 or more years. Design would require about 1 year, and construction would require about 1 year.
Water Quality? About the same as the existing supply. Some of the supply would be coming from a different surface water source that would have slightly different quality than the current supply.
Timing of availability? (by month) Same as the existing supply.
Location of the “developed” water? A reservoir on the San Bernard River, near Boling
Impacts? The major impacts are associated with inundation of the reservoir area and modification of downstream flows, which may affect bay and estuary inflow in the San Bernard basin.
- Irrigators The implementation of a water importation strategy would bring in new water. Thus, the transfer of water to Williamson County would not affect the irrigators’ annual yield.
- Recreators Since new water is brought in through water importation strategies, the transfer of water to Williamson County would not affect the Lake levels. Thus, persons who use the Lakes for recreation purposes would continue their practices without any harm.
- Downstream water right holders Since new water is brought in through water importation strategies, the transfer of water to Williamson County would not affect the availability of water to the water right holders downstream of the Lakes.
- Williamson County water users Surcharge rate would reflect the cost associated with this specific strategy.
- Environment/Biota As a matter of law and policy, the LCRA will meet subsistence and critical flows to support the strength and diversity of aquatic life in river, estuary and bay. “LCRA has committed an average of 15,950 acre-feet per year out of the Combined Firm Yield of the Highland Lakes to meet the instream flow maintenance and bays and estuaries flow needs. Additionally, an estimated 40,060 acre-feet per year of interruptible stored water will be supplied during the critical drought for both purposes.”
