Frequently Asked Questions
Q: Is the dam going to fail?
A: By keeping the pool at or below elevation 2585.5, or 20 ft below full pool, the dam will be maintained in a safe condition. This is the responsible and appropriate action while we are investigating this concern and determining corrective measures.
Q: Was the dam poorly constructed?
A: The dam was built properly at the time using the engineering technology of that era. As new engineering methods have emerged, the dam’s construction by today’s standards is inadequate.
Q: What is seepage?
A: Seepage is when water passes through or under a dam. Minor seepage is common to all dams but should be monitored to ensure that it is minimal, collected safely, and not damaging to the integrity of the dam.
Q: How bad is the seepage at the Lake Isabella Dam?
A: Both the main dam and the auxiliary dam have always experienced minor seepage. Currently the dam is safe and we do not see an increase in seepage; however, instrumentation that monitors water pressure along the dams indicates that the water pressure near the downstream end of the auxiliary dam has significantly increased over the years. This heightened the Corps’ concern and, after further study, prompted the Corps to implement the pool restriction.
Q: Should the lake be drained until the corrective work is completed?
A: Corps and State experts, backed by tests and studies, have determined that lowering the reservoir pool by 20 feet ensures the dam is safe.
Q: Will recreation activities be restricted or halted on the lake or Kern River?
A: We do not expect this pool restriction or the release of water to restrict activities on the lake. However, due to increased water releases from the dam, Kern River water flows will increase and create very dangerous river conditions. These increased water flows are affected by both the pool restriction and by management of the melting snowpack.
Q: Who will pay for the corrective measures?
A: Until we complete the analysis and study to determine the extent of the seepage and seismic issues, we won’t know for sure. If the construction falls under the Corps’ Dam Safety Assurance Program, the Army Corps of Engineers will pay for virtually all of the costs associated with the seismic improvements.
Q: Will the construction address both seepage and seismic issues?
A: That is the plan at this time. If it is possible and efficient to separate the two, the higher risk seepage problem would be solved first.
Q: How will this impact fish populations? Habitat?
A: The impact should be minimal. Reservoir levels have exceeded 360,000 acre feet – the proposed pool restriction level – only two years in the past ten and only 20 times in the past 50 years.
Q: Will the pool restriction mean water users will lose water this year?
A: We expect that all the water users will receive their full allotment this year. There is plenty of snowpack and we have a lot of flexibility to move water around in the system.
Q: Are the funds available to repair the dam?
A: The President’s budget for 2007 currently provides $2 million, which would help fund identifying seepage and seismic concerns. It is estimated that construction of the determined solution could begin as early as 2012, assuming that optimum funding is provided for prior study/design phases.
