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Orchard dam is an earthfill structure approximately 1050 feet long and 27.5 feet high. The visual inspection revealed one item that should be taken care of before refilling the reservoir. Maintenance is performed by the owner. However, there is no regular maintenance operation program or emergency operations and warning plan. It is recommended that a regular maintenance and operations program be instituted with provisions for accurate records of all maintenance performed. It is also recommened that a warning system be established and that the maintenance items listed in Section 7.2 be accomplished as a part of the regular maintenance program within the next 12 months., Prepared in cooperation with Commonwealth of Virginia State Water Control Board, Richmond, VA.

Williams Dam is an earthfill dam about 250 feet long and 28.6 feet high. Based on criteria established by the Department of the Army, Office of the Chief of Engineers (OCE), the Spillway Design Flood (SDF) is the 1/2 PMF. The emergency spillway will pass 11 percent of the PMF or 22 percent of the SDF without overtopping the crest of the dam. The SDF will overtop the dam by a maximum of 2.15 feet, reach an average critical velocity of 5.6 feet per second and flow over the dam for 3.75 hours. Flows overtopping the dam during the SDF are not considered detrimental to the embankment. The spillway is adjudged inadequate but not seriously inadequate. The visual inspection revealed no apparent problems or remedial measures in need of immediate attention. A stability check of the dam is not required. It is recommended that a formal maintenance program and warning system be established.

The dam is classified as a small size dam with a significant hazard classification. The primary spillway consists of five 6-inch diameter PVC pipes passing through the concrete wier forming the secondary spillway. The spillways will pass 16 percent of the PMF or about 50 percent of the SDF without overtopping the dam. The spillways are adjudged as inadequate but not seriously inadequate. The visual inspection revealed no apparent problems and there are no immediate needs for remedial measures., Original contains color plates: All DTIC and NTIS reproductions will be in black and white.

The Dam is an earthfill structure about 738 feet long and 40.5 feet high. The dam is classified as 'intermediate' on the basis of size, and given a hazard classification of 'significant' on the basis of downstream area development. The principal spillway consists of an octagonally shaped concrete riser with eight rectangular openings serving as drop inlets. The emergency spillway is an open concrete channel cut at the right abutment. The spillway will pass 41 percent of the PMF or 82 percent of the SDF without overtopping the crest of the dam. The spillway is adjudged inadequate but not seriously inadequate. The visual inspection revealed no apparent problems and there are no immediate needs for remedial measures., Original contains color plates: All DTIC and NTIS reproductions will be in black and white.

The Dam is an earthfill structure about 800 feet long and 29.4 feet high. The dam is classified as a small dam with a significant hazard classification. The principal spillway is a drop-inlet located in the reservoir discharges into a stilling basin below the dam. The emergency spillway is an open channel cut in the right abutment. The spillway will pass 25 percent of the PMF or 100 percent of the SDF without overtopping the crest of the dam. The spillway are adjusted as adequate. The visual inspection revealed an upstream slope failure. Therefore, the dam is assessed as unsafe, non-emergency. The 'unsafe, non-emergency' classification applied to a dam with a structural deficiency is means that based on an initial screening and preliminary calculations, there appears to be a serious deficiency in the stability of the upstream slope. It is recommended that within 2 months from the date of notification the owners engage the services of a qualified geotechnical engineering firm to perform a stability analysis on the dam and recommend methods of eliminating the danger imposed by the project. In the interim, a detailed emergency operations plan and warning system, should be promptly developed., Original contains color plates: All DTIC and NTIS reproductions will be in black and white.

The Dam is an earthfill structure about 1000 feet long and 23.3 feet high with a gravel roadway traversing the entire dam. The dam is classified as small on the basis of size, and given a hazard classification of significant on the basis of downstream area development. The principal spillway consists of a 42-inch diameter corrugated metal pipe (CMP) vertical riser connected to a 36-inch diameter CMP which passes through the dam at a low level. The emergency spillway is an open earth channel cut in the left abutment. The spillways will pass 10 percent of the PMF or 20 percent of the SDF without overtopping the crest of the dam. The spillway is adjudged inadequate but not seriously inadequate. The visual inspection revealed that there are no immediate needs for remedial measures, except for the monitoring of the spring beneath the primary spillway outlet. It is recommended that a regular maintenance and operations program be instituted with provisions for accurate records of all maintenance performed., Original contains color plates: All DTIC and NTIS reproductions will be in black and white.

The Dam is an earthfill structure about 230 feet long and 19 feet high with a private roadway traversing the dam. The dam is classified as small size with a significant hazard classification. The pipe spillway is a 10-inch cast iron metal pipe drop-inlet that connects to a 10-inch cast iron metal pipe which passes through the dam at low level and an open channel cut at the left abutment. The spillways will pass 7 percent of the PMF or 36 percent of the SDF without overtopping the crest of the dam. The effects of overtopping from the SDF are not considered detrimental to the embankment. The spillway is adjudged as inadequate, but not seriously inadequate. The visual inspection revealed no problems in need of immediate attention. However, there is no regular maintenance operations program or warning system. It is recommended that a regular maintenance and operations program be instituted with provisions for records of all maintenance performed., Original contains color plates: All DTIC and NTIS reproductions will be in black and white.

The Dam is an earthfill structure approximately 250 feet long and 26.1 feet high. The dam is classified as a small size dam with a significant hazard classification. The principal spillway is a concrete open channel located at the right abutment. The emergency spillway is a low area left of the dam used as an access road. The spillway is capable of passing 13 percent of the PMF without overtopping the crest of the dam. The spillway is adjudged as inadequate, but not seriously inadequate. The visual inspection revealed a seep on the downstream slope with evidence of piping. Also a shallow 12-foot wide depression was noted 40 feet right of the seep. It is recommended that a geotechnical engineering firm be retained within six months to evaluate the possible piping and the cause for the 12-foot wide depression. It is also recommended that within 12 months a regular maintenance program be initiated to maintain the integrity of the structure., Original contains color plates: All DTIC and NTIS reproductions will be in black and white.

The dam is an earthfill structure about 800 feet long and 45.2 feet high. The dam is classified as an intermediate size dam with a significant hazard classification. The designed principal spillway is a 10-inch steel drop-inlet stand pipe located in the reservoir. Because of underlying cavernous limestone beneath the reservoir, the water level is considerably below the normal design pool. There are two emergency spillways. The left emergency spillway is an open channel spillway which is a low point in natural ground. The right emergency spillway is an open channel cut into natural ground. The spillways will pass the PMF without overtopping; therefore, the spillways are adjudged as adequate. The visual inspection revealed no apparent problems or remedial measures in need of immediate attention., Original contains color plates: All DTIC and NTIS reproductions will be in black and white.

Based on criteria established by the Department of the Army, Office of the Chief of Engineers (OCE), the Spillway Design Flood (SDF) is the 100-Year Flood. The spillway will pass 20 percent of the PMF or 100 percent of the SDF without overtopping the crest of the dam. The spillways are adjudged as adequate. The visual inspection revealed no apparent problems and there are no immediate needs for remedial measures. However, the upstream slope and crest width are inadequate and there is no design data or construction history. Maintenance is performed by the owner, but there is no regular maintenance operations program or warning system. It is recommended that the services of a qualified geotechnical engineering firm be engaged to perform a stability check of the dam. This should be completed within 12 months. It is also recommended that a regular maintenance and operations program be instituted with provisions for accurate records of all maintenance performed, and that a warning system be established. The maintenance items listed in Section 7.2 be accomplished as part of the regular maintenance program within the next 12 months., Original contains color plates: All DTIC and NTIS reproductions will be in black and white.

Cage Dam is an earthfill structure about 400 feet long and 26.3 feet high with a 13-foot crest. Based on criteria established by the Department of the Army, Office of the Chief of Engineers (OCE), the Spillway Design Flood (SDF) is the 1/2 PMF (Probable Maximum Flood). The spillway will pass 12 percent of the PMF or 24 percent of the SDF without overtopping the crest of the dam. The SDF will overtop the dam by 0.9 feet for 3.0 hours and attain a critical velocity of 4.4 feet per second. Overtopping velocities are not considered detrimental to the structure. The spillway is adjudged as inadequate, but not seriously inadequate. The visual inspection revealed no problems in need of immediate attention. Maintenance is performed by the owner. However, there is no regular maintenance operations program or warning system. It is recommended that a regular maintenance and operations program be instituted with provisions for records of all maintenance performed. It is also recommended that warning system be established and that the maintenance items listed in Section 7.2 be accomplished as part of the regular maintenance program within the next 12 months., Prepared in cooperation with Commonwealth of Virginia State Water Control Board, Richmond, VA.

Hidden Valley Lake Dam is an earthfill embankment structure about 560 feet long and 32.3 feet high. The dam is classified as an intermediate size dam with a significant hazard classification. The principal spillway is a concrete drop-inlet riser, and the emergency spillway is an open channel in the right abutment. The dam is used for recreation. Based on criteria established by the Department of the Army, Office of the Chief of Engineers (OCE), the Spillway Design Flood (SDF) is the 1/2 PMF. The spillways will pass 39 percent of the PMF or 78 percent of the SDF without overtopping the dam. The SDF will overtop the dam by 1.1 feet, reach an average critical velocity of 4.8 feet per second (fps) and flow over the dam for 2.5 hours. Flows overtopping the dam during the SDF are not considered detrimental to the structure. The spillways are adjudged as inadequate, but not seriously inadequate.

The Elon Water Works Dam is a zoned earth fill dam approximately 52.1 feet high and 490 feet long. The dam is classified as an intermediate size dam with a significant hazard classification. The emergency spillway is an earthen channel with a trapezoidal cross section at the left abutment. The principal spillway is a concrete drop-inlet with a fixed crest elevation of 663 feet. The reservoir is used for water supply. Based on criteria established by the Department of the Army, Office of the Chief of Engineers (OCE), the Spillway Design Flood (SDF) is the 1/2 PMF. The emergency spillway will pass 32 percent of the PMF or 64 percent of the SDF without overtopping the dam. The SDF will overtop the dam by a maximum of 1.2 feet, reach an average critical velocity of 5.1 feet per second and flow over the dam for 2.4 hours. The emergency spillway is adjudged inadequate, but not seriously inadequate.

The Moore Dam is an earthfill stucture about 400 feet long and 22.7 feet high with a private roadway traversing the dam. The dam is classified as small size with a significant hazard classification. The principal spillway is a 24-inch corrugated metal pipe drop-inlet that connects to a 15-inch corrugated metal pipe which passes through the dam at low level. The emergency spillway is an open channel cut at the left abutment. The reservoir is used for recreation and irrigation by the owner. Based on criteria established by the Department of the Army, Office of the Chief of Engineers (OCE), the Spillway Design Flood (SDF) is the 100 year flood. The spillways will pass 24 percent of the PMF or 100 percent of the SDF without overtopping the crest of the dam. The spillway is adjudged as adquate.

Upper and Lower Apple Mountain Dams are two impounding structures with the tailwater of the Upper Dam being the reservoir water surface of the Lower Dam. The Upper Dam is an earthen embankment about 351 feet long and 34.5 feet high, while the Lower Lake Dam is an earthen embankment about 377 feet long and 32.9 feet high. The dams are classified as small dams with a hazard classification of significant based on location. The emergency spillway for each dam is an earthen channel located at the left abutment of each dam. Based on criteria established by the Department of the Army, Office of the Chief of Engineers (OCE), the Spillway Design Flood (SDF) is the 100-year flood for each. The emergency spillway of the upper dam will pass 6 percent of the PMF and 100 percent of the SDF without overtopping while the lower dam will pass 4 percent of the PMF and 100 percent of the SDF without overtopping. Therefore, the spillway of each dam is adjudged as adequate.

The dam is classified as a small size dam with a significant hazard classification. The spillway consists concrete rectangular notch 1.4 feet deep and 85 feet long across the center portion of the dam. The reservoir is used for recreation and limited grist mill operation. Based on criteria established by the Department of the Army, Office of the Chief of Engineers (OCE), the Spillway Design Flood (SDF) is the 100 Year Flood. The spillway will pass 3 percent of the PMF or about 10 percent of the SDF without overtopping the dam. The SDF will overtop the dam by a maximum 2.86 feet, reach an average critical velocity of 8.0 feet per second (fps) and flow over the dam for 7 hours. The spillway is adjudged inadequate but not seriously inadequate.

Loch Haven Dam is a concrete structure about 79.5 feet long and 25 feet high. The dam is classified as a small dam with a significant hazard classification. The principal spillway is a 5-inch cast iron pipe that passes through the dam. The secondary spillway is a rectangular cut near the center of the dam. An 8-inch PVC siphon pipe is available for lowering the water level in the reservoir below the principal spillway intake. The reservoir provides recreation for various community civic organizations, local businesses, members of the Loch Haven Country Club, and six families living on the property. Based on criteria established by the Department of the Army, Office of the Chief of Engineers (OCE), the Spillway Design Flood (SDF) is the 100 Year Flood. The secondary spillway will pass 4 percent of the PMF or 17 percent of the SDF without overtopping the crest of the dam. The SDF will overtop the dam by a maximum 3.66 feet, reach an average critical velocity of 9.1 feet per second and flow over the dam for 6.75 hours. The overtopping velocities are not considered detrimental to the dam. The secondary spillway is adjudged inadequate but not seriously inadequate.

Mitchells Dam is an earthfill structure about 350 feet long and 54.9 feet high. The dam is classified as an intermediate size dam with a significant hazard classification. The principal spillway is a 5-inch steel drop-inlet located in the left portion of the reservoir. The emergency spillway is an open channel cut into the right abutment. The reservoir offers minimal recreation. Based on criteria established by the Department of the Army, Office of the Chief of Engineers (OCE), the Spillway Design Flood (SDF) is the 1/2 PMF. The emergency spillway is capable of passing the SDF. The spillway is adjudged adequate.

Warrenton Dam is comprised of a 550 foot long concrete slab and buttress dam and two earthen dikes separated by a grassy knoll. The dikes are in the reservoir located in a low lying area north of the dam. One dike is about 300 feet long and 13 feet high. The other dike, perpendicular to the first, is about 175 feet long and 6 feet high. A concrete intake structure comprised of three 8-inch intakes at different elevations allows flow to discharge into the stream below the dam, furnishing water to the Warrenton Filtration Plant about 2 miles downstream. The concrete intake structure also has a 24-inch inlet and a 24-inch outlet. The maximum height is 30.8 feet for the concrete spillway. The dam is located 0.5 miles north of the Warrenton town limits and is used as the water supply for Warrenton, Virginia. The dam is owned and maintained by the Town of Warrenton, Virginia. The dam is classified as a small dam with a significant hazard classification. Based on criteria established by the Department of the Army Office of the Chief of Engineers (OCE), the Spillway Design Flood (SDF) is the 100 year flood. Since the spillway was sized for the 21 percent PMF, which is greater than the 100 year flood, the spillway is adjudged as adequate.

Bedford Lake Dam is located approximately 0.5 miles northwest of Colton's Mill, Virginia, at the headwaters of the North Otter Creek. The field inspection was conducted on April 1, 1981. The weather was clear and dry with a temperature in the low seventies. Ground surface conditions along the embankment were generally dry. At the time of the inspection the pool elevation was at 993.3 msl and the tailwater elevation was approximately 952.6 msl. Overall the dam and appurtenant structures were found to be in good condition. However, several deficiencies were found necessitating remedial treatment. A field sketch of the conditions observed during the inspection is located in Appendix I. Prior to the present owners purchase of the dam, an inspection and evaluation was performed by the firm of Hurt and Profitt Engineers-Surveyors, Lynchburg, Virginia. At their recommendation the bridge spanning the emergency spillway was replaced and remedial work was done to the ogee weir at the entrance to the emergency spillway channel.

Laurel Creek Dam is an earthen structure about 250 feet long and 17.5 feet high. The dam is classified as a small dam with a significant hazard classification. The principal spillway is a 30-inch corrugated metal pipe (CMP) drop-inlet with a 36-inch CMP control at normal pool. The emergency spillway is an open channel cut in the left abutment. The reservoir is used for recreation. Based on criteria established by the Department of the Army, Office of the Chief of Engineers (OCE), the Spillway Design Flood (SDF) is the 100 Year Flood. The spillway will pass 9 percent of the PMF or 19 percent of the SDF without overtopping the crest of the dam. The SDF will overtop the dam by about 1 foot, flow over the dam about 4 hours and reach a maximum velocity of 4.6 feet per second. Overtopping velocities are not considered detrimental to the dam. The spillway is adjudged as inadequate but not seriously inadequate.

The purpose of a Phase I investigation is to identify expeditiously those dams which may pose hazards to human life or property. The assessment of the general conditions of the dam is based upon available data and visual inspections. Detailed investigations and analyses involving topographic mapping, subsurface investigations, testing, and detailed computational evaluations are beyond the scope of Phase I investigation; however, the investigation is intended to identify any need for such studies. Based upon the field conditions at the time of the field inspection and all available engineering data, the Phase I report addresses the hydraulic, hydrologic, geologic, geotechnic, and structural aspects of the dam. The engineering techniques employed give a reasonably accurate assessment of the conditions of the dam. It should be realized that certain engineering aspects cannot be fully analyzed during a Phase I inspection. Assessment and remedial measures in the report include the requirement of additional indepth study when necessary. Phase I reports include project information of the dam and appurtenances, all existing engineering data, operational procedures, hydraulic/hydrologic data of the watershed, dam stability, visual inspection report and an assessment including required remedial measures., Original contains color plates: All DTIC and NTIS reproductions will be in black and white.

The purpose of a Phase I investigation is to identify expeditiously those dams which may pose hazards to human life and property. The assessment of the general conditions of the dam is based upon available data and visual inspections. Detailed investigation and analyses involving topographic mapping, subsurface investigations, testing, and detailed computational evaluations are beyond the scope of a Phase I investigation; however, the investigation is intended to identify any need for such studies. Based upon the field conditions at the time of the field inspection and all available engineering data, the Phase I report addresses the hydraulic, hydrologic, geologic, geotechnic, and structural aspects of the dam. The engineering techniques employed give a reasonably accurate assessment of the conditions of the dam. It should be realized that certain engineering aspects cannot be fully analyzed during a Phase I inspection. Phase I reports include project information of the dam and appurtenances, all existing engineering data, operational procedures, hydraulic/hydrologic data of the watershed, dam stability, visual inspection report and an assessment including required remedial measures.

The purpose of a Phase I investigation is to identify expeditiously those dams which may pose hazards to human life or property. The assessment of the general conditions of the dam is based upon available data and visual inspections. Detailed investigation and analyses involving topographic mapping, subsurface investigations, testing, and detailed computational evaluations are beyond the scope of a Phase I investigation; however, the investigation is intended to identify any need for such studies. Based upon the field conditions at the time of the field inspection and all available engineering data, the Phase I report addresses the hydraulic, hydrologic, geologic, geotechnic, and structural aspects of the dam. The engineering techniques employed give a reasonably accurate assessment of the conditions of the dam. It should be realized that certain engineering aspects cannot be fully analyzed during a Phase I inspection. Phase I reports include project information of the dam and appurtenances, all existing engineering data, operational procedures, hydraulic/hydrologic data of the watershed, dam stability, visual inspection report and an assessment including required remedial measures.