Efficiently and responsibly managing and protecting our water and land resources for the sustainability, health, safety, and economic benefit of the State of Arkansas
To provide for the comprehensive regulation and supervision of dams for the health, safety, and welfare of the citizens of Arkansas. To assure proper planning, design, construction, maintenance, monitoring, and supervision of dams, including such preventative measures necessary to provide and adequate margin of safety.
Subchapter 2 of Chapter 22 of Title 15 of the Arkansas Code of 1987, as amended, authorizes the Arkansas Natural Resources Commission to develop and enforce rules and regulations governing the design and operation of dams in the State.
All dams with height of 25 or more feet and containing 50 acre-feet or more of storage at normal pool must have a valid construction and operation permit from the Commission, unless they are owned by the United States Government. If smaller dams pose a threat to life or property, they may also require regulation by the State based on petition by downstream landowners and results of public hearings.
Duties of the Dam Safety Section include
- Reviewing applications for permits to assure proper safety standards are met
- Issuing permits to construct and operate dams in the State
- Inspecting dams under State jurisdiction
- Providing information and education to dam owners and the public
- Overseeing the development and implementation of emergency action plans for high hazard dams
- Responding to dam emergencies
- Maintaining a database and files on dams in the State
- Collecting annual permit fees (handled through the Financial Affairs Office)
- Permit to construct or operate a dam in Arkansas
- Application for transfer of a dam permit
- Permitted dam update form
- Inspection form
- Rules Governing Design and Operation of Dams
- Maintenance Manual for Arkansas Dam Owners
- Dam Safety Guidance Manual
For more information contact:
Stephen C. Smedley, P.E., Dam Safety Engineering Supervisor
Probable Maximum Precipitation Study
The 2019 Probable Maximum Precipitation (PMP) Study was implemented as a peer-reviewed investigation, using existing methodologies and science to create updated data, tools, and procedures for estimating extreme precipitation depth, area, and duration relationships for the regional area including Arkansas, Louisiana, and Mississippi. Historically, PMP rainfall depths for spillway design were estimated using Hydrometeorological Reports [HMRs] 51, 52, and 55A provided by the National Oceanic and Atmospheric Administration (NOAA).
These HMRs are increasingly viewed as outdated and their use in dam safety regulation has become increasingly difficult to defend to dam owners and to elected officials. Like other states, Arkansas, Louisiana, and Mississippi identified and set as a priority updating extreme precipitation estimates for use in the evaluation of spillway adequacy. Due to the similarities in geography and meteorology between the three states, a cooperative, regional approach was proposed.
The ultimate goal of the PMP Study was creation of updated, broadly accepted GIS-based tool for estimating PMP precipitation depth, area, and duration relationships for individual basins within the Arkansas/Louisiana/ Mississippi region. This tool – the PMP Evaluation Tool – is available for use by the engineering and dam safety community.
PMP Evaluation Tool
The PMP Evaluation Tool uses a Python-based script designed to run within the ArcGIS environment. ESRI’s ArcGIS Desktop Basic software, version 1.4 or later, is required to run the tool, and it is recommended that the user have a basic familiarity with the operation of this software. The tool provides gridded PMP values at a spatial resolution of 90 arc-seconds (equivalent to .025 x .025 decimal degrees) for a user-designated drainage basin or area at user-specified durations, in addition to basin average PMP depths and temporally distributed accumulations.
Questions regarding use of this tool can be directed to the State Climatologist at firstname.lastname@example.org.