WATERSHED FLOOD CONTROL STRUCTURES
The Peter Francisco Soil & Water Conservation District (PFSWCD) has 17 USDA Natural Resource Conservation Service (NRCS) assisted watershed projects located in Buckingham and Cumberland Counties, providing flood protection for both counties.
Over 150 watershed dams have been built across the state of Virginia with financial and technical assistance from NRCS authorized through the Public Law 83-566 Watershed Project and Flood Prevention Program. PFSWCD is the Local sponsor of the projects that benefit Buckingham and Cumberland. PFSWCD’s primary responsibility is to operate and maintain the watershed flood control structures, to prepare and update emergency action plans and maintain regulatory certifications with the Department of Conservation and Recreation (DCR). PFSWCD coordinates with both Buckingham and Cumberland Counties in emergency action planning and implementation.
The PFSWCD sponsored watershed projects were originally planned and implemented for flood control and soil erosion reduction. The projects provide other community natural resource benefits such as water quality, irrigation water management, water supplies, wetland development, fish and wildlife habitat and recreation. Projects of this nature have been providing benefits for decades, but people are often unaware that the projects even exist, because of their rural setting.
How do Watershed Flood Control Dams Reduce Flooding?
The concept of watershed projects is simple. A series of watershed dams are built across small tributaries to larger streams. The dams temporarily store flood water after rain storms and slowly release it over a period of several days through a pipe in the dam. This slows the surge of water that reaches the main water course after a rain, thus reducing flooding. Land conservation programs in the watershed help control erosion, which will reduce the sediment that flows into streams and lakes.
Facts & Figures
There are eleven (11) flood control dams located in the Willis River watershed and six (6) in the Slate River watershed. All are earthen dams with primary and secondary spillways. The Willis River watershed dams were constructed during the time period of 1969-1975 and the Slate River watershed dams were constructed between the years of 1961-1991. The surrounding land and lakes are privately owned with the majority of the land use in forest and agriculture.
The Willis River watershed consists of 176,700 acres. 50% of the watershed is in the eastern portion of Buckingham and 50% in the western portion of Cumberland.
The Slate River watershed consists of 98,730 acre, with 7,450 of those acres in the smaller watershed of Muddy Creek. The towns of Buckingham and Dillwyn, and majority of Buckingham are included in the Slate River watershed area.
Operation and Maintenance Performed
Operation and maintenance of the watershed dams can be expensive and labor intensive, but is necessary to ensure the dams function as designed and remain safe.
Maintenance work includes:
annual mowing of dams
clearing trees from dams, abutments and spillways
repairing soil erosion damage to the spillway and dam after heavy storm events
testing the water inlet pipe gates
monitoring for wet areas on dam structure
keeping the inlet towers cleared of debris.
As required by state laws and regulations, annual maintenance inspections are performed, in addition to inspections after storm events.
Emergency Action Planning
Every flood control dam has an Emergency Action Plan (EAP) that is a part of the requirement for certification from the Department of Conservation and Recreation - Dam Safety. Our EAP’s are developed and coordinated with Buckingham and Cumberland County Emergency Services.
The EAP contains the following information: amount of rainfall that initiates flood conditions; road and bridges downstream that might be impacted; calling diagram for possible evacuation and a list of downstream landowners, businesses, etc that could be at risk. The EAP is reviewed annually.
A ‘table-top’ exercise with PFSWCD and emergency services is performed in accordance with regulations.
In addition to an EAP, each dam has a flood level gauge located in the control section of the emergency spillway, which are monitored during a storm event.
Downstream Development – Flood Inundation Areas & Sponsors Concerns
Development downstream of flood control dams is a growing concern for watershed projects across the country. Downstream development may result in higher hazard classification of the dam, more stringent regulations, more extensive emergency action plans and most likely rehabilitation of dam to meet dam safety standards.
The majority of the dams constructed to protect Buckingham and Cumberland Counties were constructed as low-hazard dams to protect rural agricultural land and surrounding towns. New regulations passed in 2009 now require all regulated dams to have a flood inundation study performed. DCR, along with engineering contractors, have conducted flood inundation studies and mapping for the 17 PFSWCD watershed dams. These studies delineate potential downstream flooding areas in the event of a dam breach.
As a result of the studies, PFSWCD has three (3) dams classified as “significant hazard” and fourteen (14) as “high hazard”. Significant hazard usually indicates a secondary road downstream could be impacted and High hazard designation (in the case of PFSWCD’s dams), is due to either a residence within a flood inundation area or potential impacts to state highways. This hazard change means upgrades are required to PFSWCD spillways and dams.
If you have a question about our dam structures, please contact Kelly Snoddy, Conservation Specialist.