As of December 2003, there are 77,406 dams listed in the United States Dam Inventory. Of those, 2,110 dams (less than 3%) are owned by the federal government. The remaining dams are either privately owned or owned by local or state governments. The State of Nevada, through Nevada Revised Statutes (NRS) Chapter 535
, charges the State Engineer with responsibility for public safety in relation to those dams in the State. The State Engineer has adopted regulations under Nevada Administrative Code (NAC) Chapter 535
for the administration of the safety of dams program.
Dams that store mobile fluids are hazardous by their very nature. Failures generally result in major damage downstream due to the rapid release of energy in the form of impounded fluid or semi-fluid material. Damage can be physical, i.e. houses, farmland or infrastructure, or in the case of industrial ponds and effluent dams, the release of hazardous material into the environment.
The responsibility of the State Engineer for safety of dams is addressed by four primary areas of activity:
- Review of plans and specifications. New dam construction, reconstruction or alteration of existing dams must be reviewed for conformance with design standards and effective construction techniques. Experienced registered professional engineers in the Engineering and Safety of Dams Section conduct these reviews and work closely with the design engineers in order to provide a safe and workable design and construction plan. Upon approval of the plans and specifications, authorization is given to the owner to allow the start of construction. Water right issues are also addressed at the time of review.
- Approval to impound. Record drawings ("as-built"), QA/QC documentation and project engineer's certification of construction are reviewed for content and accordance with conditions of the permit. Upon approval, an authorization to impound is issued to the owner.
- Physical inspection of dams. Periodic inspections are conducted by experienced engineers on staff in the office of the State Engineer. Based upon conditions identified during these inspections, dam owners are directed to take action to correct all identified deficiencies. The inspector is available to review questionable conditions on site with the dam owner, explain problems and suggest methods for mitigation of any identified deficiencies to assure the dam's continued safe operation. Storage restrictions may be ordered to protect the safety of downstream areas. Further studies by a qualified engineer are recommended in many cases.
- Periodic inspection of construction. Work carried out on new or existing dams may be inspected at crucial points. These inspections are performed in order to verify that the work conforms to the approved plans and specification. Any problem or corrective action that is discussed with the project engineer is identified and implemented.
The information on the following pages is intended to assist an applicant in understanding the preparation of an application, design, specifications and drawings to be submitted for approval, and also to inform the general public as to the role that the State of Nevada plays in regard to dam safety. Questions about details on the specific process of dam design should be directed to an engineer qualified in the design of dams or to staff engineers in the office of the State Engineer.