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Author: United States. Army. Corps of Engineers. St. Louis District
Publisher:
Published: 1978
Total Pages: 94
ISBN-13:
DOWNLOAD EBOOK →Author: Henry M. Reitz
Publisher:
Published: 1978
Total Pages: 47
ISBN-13:
DOWNLOAD EBOOK →Fon-du-lac Subdivision Dam was inspected by an interdisciplinary team of engineers. The purpose of the inspection was to make an assessment of the general condition of the dam with respect to safety, based upon available data and visual inspection, in order to determine if the dam poses hazards to human life or property. Failure would threaten the life and property of ten families and cause appreciable damage to two county roads. Our inspection and evaluation indicates the dam is deficient in that the spillway is inadequate. The guidelines for a dam having the above size and hazard potential require that the spillway be capable of passing a one-half PMF (Probable Maximum Flood). The Probable Maximum Flood is defined as the flood discharge that may be expected from the most severe combination of critical meteorologic and hydrologic conditions reasonably possible in the region. Considering the small volume of water impounded, the large floodplain downstream and the three groups of farm buildings downstream, one-half PMF is the appropriate spillway design flood. A 20% PMF will begin to overtop the dam. The lake and spillway are adequate to contain a 1% annual probability flood (100-year flood) without overtopping the dam.
Author: Henry M. Reitz
Publisher:
Published: 1978
Total Pages: 52
ISBN-13:
DOWNLOAD EBOOK →The purpose of the inspection was to make an assessment of the general condition of the dam with respect to safety, based upon available data and visual inspection to determine if the dam poses hazards to human life or property. The inspection and evaluation indicates that the dam is deficient in that the spillways do not meet the criteria set forth in the guidelines for a dam having the above size and hazard potential. Considering the volume of water impounded, the floodplain downstream and potential residential development downstream, the Probable Maximum Flood (PMF) is the appropriate spillway design flood. The probable maximum flood is defined as the flood discharge that may be expected from the most severe combination of critical meteorological and hydrologic conditions reasonably possible in the region. The dam will begin to be overtopped by a flood having a discharge (peak and volume) equal to 50% of the PMF. The spillways will pass 1% chance flood (100-year flood) without overtopping, which is a flood that has a 1% chance of being equalled or exceeded in any given year. There were indications of seepage or underseepage through or under the dam embankment. This is a serious safety deficiency which could lead to failure of the embankment.
Author: Henry M. Reitz
Publisher:
Published: 1978
Total Pages: 51
ISBN-13:
DOWNLOAD EBOOK →The purpose of the inspection was to make an assessment of the general condition of the dam with respect to safety, based upon available data and visual inspection, in order to determine if the dam poses hazards to human life or property. The inspection and evaluation indicates that the dam is deficient in that the spillways do not meet the criteria set forth in the guidelines for a dam having the above size and hazard potential. Considering the volume of water impounded, the small floodplain downstream and the 25 buildings downstream, the Probable Maximum Flood (PMF) is the appropriate spillway design flood. The probable maximum flood is defined as the flood discharge that may be expected from the most severe combination of critical meteorological and hydrologic conditions reasonably possible in the region. The dam will begin to be overtopped by a flood having a discharge (peak and volume) equal to 45% of the PMF. The spillways will pass 1% chance flood (100-year flood) without overtopping which is a flood that has a 1% chance of being exceeded in any given year. Other deficiencies noted by the inspection team were underseepage or seepage at the base of the dam embankment and heavy growth of trees and shrubs on the downstream slope of the dam.
Author: Arthur L. Johnson
Publisher:
Published: 1978
Total Pages: 40
ISBN-13:
DOWNLOAD EBOOK →This report assesses the general condition of the dam with respect to safety, based on available data and on visual inspection, to determine if the dam poses hazards to human life or property. The dam is in the high hazard potential classification, which means that loss of life and appreciable property loss could occur in the event of failure of the dam. For its size and hazard category, this dam is required by the guidelines to pass one-half PMF to the PMF. The spillway of this dam will pass only 20 percent of the PMF without overtopping the dam. Since the spillway for Sweetwater Dam is not capable of passing a minimum of one-half (50 percent) of the PMF without overtopping the dam, the spillway is considered inadequate. The inspection team observed heavy tree growth covering the downstream slope of the dam and spillways. Potential exists for other deficiencies such as rodent holes to be found after the trees and brush have been removed. The downstream slope of the dam was eroded considerably in the area of the right abutment where flow from the right spillway has occurred int he past. Seepage and stability analyses are not on record as recommended in the guidelines, which is considered a deficiency that should be rectified.
Author: Richard G. Berggreen
Publisher:
Published: 1980
Total Pages: 63
ISBN-13:
DOWNLOAD EBOOK →Lower Valle Mines Dam is classified as small, based on its storage capacity of 78 ac-ft. The dam is 22 ft in height. The small dam classification applies to dams between 25 and 40 ft high, or those with storage volume between 50 and 1000 ac-ft. The St. Louis District, Corps of Engineers, has classified this dam as having a high hazard potential; we concur with this classification. The estimated damage zone length extends approximately two miles downstream of the dam. Within this estimated damage zone are two improved roads, the dam and reservoir at Lake Valle, and numerous vacation and permanent dwellings on the shores of the lake. The potential for loss of life and property may be high in the event of a dam failure. Lower Valle Mines Dam is an earth dam, densely vegetated with brush and trees. There are two spillways, the main spillway on the left or west abutment and the auxiliary spillway on the east abutment. The visual inspection and evaluation of available data indicate Lower Valle Mines Dam is in generally fair condition. This judgment is based on the potential for overtopping, and the dense vegetation on the downstream face of the embankment. The embankment materials appear moderately erodible, both the vegetation presently offers some erosion protection. Seepage in the area beyond the toe of the dam does not appear to pose a hazard to the dam at this time. The lack of periodic inspections and maintenance on the dam is considered a deficiency.
Author: Albert B Becker (Jr)
Publisher:
Published: 1978
Total Pages: 45
ISBN-13:
DOWNLOAD EBOOK →Certain deficiencies were noticed during the visual inspection and are considered to have an adverse effect on the overall safety and future operation of the dam and spillway. The upstream slope of the dam is irregular (maximum slope ratio is approximately 1v on 1.3h) beginning at a level about 12 feet below the top of the dam. Excessive irregularities of the face of the dam are indications of instability and/or erosion, both of which are considered detrimental to the safety of the dam. A substantial cover of small trees and brush that may conceal animal burrows exists on the upstream and downstream slopes of the dam. The tree roots and animal burrows can provide a pathway for lake seepage that may develop into a piping condition. The upstream slope has a grass cover to protect it from erosion by wave action. Grass cover is not considered adequate to prevent erosion by wave action for a fluctuating lake level. Loss of material can result in instability and settlement of the dam crest. A dense growth of brush and small trees obstructs the spillway crest and outlet channel.
Author: Walter G. Shifrin
Publisher:
Published: 1981
Total Pages: 84
ISBN-13:
DOWNLOAD EBOOK →Sunrise Lake Dam was inspected. The overall condition of the dam appears to be fair; however, several deficiencies were noted by the inspection team. These deficiencies included: seepage under the spillway slab; cracks and spalling of the concrete in the spillway; the erosion of the banks of the discharge channel of the spillway; the erosion of the upstream slope due to wave action; several shallow surface sloughs observed on the embankment slopes; the presence of saplingss and brush on the embankment slopes and trees along the downstream, right abutment/embankment contact; a need for periodic maintenance of the grass cover; and a lack of a maintenance schedule. There exists a need for periodic inspection by a qualified engineer. The lack of seepage and stability analyses on record is also a deficiency that should be corrected.
Author: HORNER AND SHIFRIN INC ST LOUIS MO.
Publisher:
Published: 1978
Total Pages: 61
ISBN-13:
DOWNLOAD EBOOK →Based on a visual inspection, the present general physical condition of the dam is considered to be satisfactory; however, the following deficiencies were noticed during the inspection and are considered to have an adverse effect on the overall safety and future operation of the dam: A few small trees exist on the upstream and downstream slopes of the dam. The downstream slope also has a dense cover of vegetation and brush in most areas that may contain animal burrows. A dense growth of trees and brush obstructs the spillway outlet channel downstream of the roadway culvert crossing. This growth will restrict channel flow and could require spillway discharge to overflow the channel and flood the area adjacent to the downstream toe of slope. Flooding of the area adjacent to the dam may impair the stability of the dam. An 8-inch diameter concrete pipe, located approximately 340 feet south of the spillway, passes through the dam about 2 feet below the crest. This conduit will provide an outlet for lake surcharge at an elevation below the dam crest that could result in erosion of the downstream slope of the dam. There did not appear to be a means of isolating the sanitary sewer passing through the dam should failure of the sewer line within the lake occur. Loss of water from the lake through the sewer pipe could surcharge the system to the point where it floods the area downstream of the dam. Operation of the lake can also be affected depending upon the quantity of lake water entering the sewer should failure occur.
