HJ132: Probable Maximum Precipitation (PMP); DCR to study utilization of storm-based approach in updating.

HOUSE JOINT RESOLUTION NO. 132

Offered January 13, 2014
Requesting the Department of Conservation and Recreation to study the utilization of a storm-based approach in updating the Probable Maximum Precipitation (PMP) for locations within or affecting the Commonwealth. Report.
Patron-- Byron

Unanimous consent to introduce

Referred to Committee on Rules

WHEREAS, it is the responsibility of the Virginia Soil and Water Conservation Board and the Department of Conservation and Recreation to ensure that impounding structures in the Commonwealth are properly and safely designed, constructed, maintained, and operated in order to protect public safety; and

WHEREAS, an impounding structure's spillway capacity is required to perform at a minimum to safely pass the appropriate spillway design flood for the impounding structure's determined Hazard Potential Classification; and

WHEREAS, the spillway design flood is based on the Probable Maximum Flood (PMF), which is the flood that might be expected from the most severe combination of critical meteorological and hydrologic conditions that are reasonably possible in the region; and

WHEREAS, the PMF is derived from the current Probable Maximum Precipitation (PMP) available from the National Oceanic and Atmospheric Administration's (NOAA's) National Weather Service and represents the theoretically greatest depth of precipitation for a given duration that is meteorologically possible over a given size storm area at a particular geographical location at a particular time of year with no allowance made for future long-term climatic trends; and

WHEREAS, current PMP values for the Commonwealth are based on NOAA's National Weather Service guidance produced over 30 years ago in Hydrometeorological Report (HMR) documents, including HMR 51, and for which funding for updates has ceased; and

WHEREAS, several state dam safety programs have investigated updated site-specific study approaches as an option to utilizing the generalized PMP values found in the federal HMRs that have, with only a few minor exceptions, indicated lower PMP/PMF for the basins and that have, following acceptance, resulted in significant cost savings to owners and operators for impounding structure spillway construction or remediation; now, therefore, be it

RESOLVED by the House of Delegates, the Senate concurring, That the Department of Conservation and Recreation be requested to study the utilization of a storm-based approach in updating the Probable Maximum Precipitation (PMP) for locations within or affecting the Commonwealth.

In conducting its study, the Department of Conservation and Recreation shall determine the amount of savings that may accrue to dam owners with respect to impoundment structure spillway construction or remediation efforts, if such a storm-based approach is adopted.

The Department of Conservation and Recreation may request technical assistance from the Virginia Society of Professional Engineers. All agencies of the Commonwealth shall provide assistance to the Department of Conservation and Recreation for this study, upon request.

The Department of Conservation and Recreation shall complete its meetings by November 30, 2014, and shall submit to the Governor and the General Assembly an executive summary and a report of its findings and recommendations for publication as a House or Senate document. The executive summary and report shall be submitted as provided in the procedures of the Division of Legislative Automated Systems for the processing of legislative documents and reports no later than the first day of the 2015 Regular Session of the General Assembly and shall be posted on the General Assembly's website.