Swiss Lake Estates Dam was inspected 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. Our inspection and evaluation indicates that the spillway does not meet the criteria set forth in the recommended guidelines for a small dam having a high hazard potential. Considering the volume of water impounded and the number of dwellings downstream of the dam, one-half of the Probable Maximum Flood is the appropriate spillway design flood. The spillways will pass the 100-year flood (flood having a one percent chance of being exceeded in any year) without overtopping the dam. The spillways will pass 20% of the Probable Maximum Flood without overtopping the dam. The Probable Maximum Flood (PMF) is defined as the flood that may be expected from the most severe combination of critical meteorologic and hydrologic conditions that are reasonably possible in the region.

This report presents the results of field inspection and evaluation of the Hilliard Estates Lake Dam (MO No. 20473). It was prepared under the National Program of Inspection of Non-Federal Dams. This dam has been classified as unsafe, non-emergency by the St. Louis District as a result of the application of the following criteria: The combined spillway capacity will not pass 50 percent of the Probable Maximum Flood without overtopping the dam. Overtopping of the dam could result in failure of the dam. Dam failure significantly increases the hazard to loss of life downstream.

Lake Northwoods Dam was inspected 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. Our inspection and evaluation indicates that the spillway does not meet the criteria set forth in the recommended guidelines for an intermediate dam having a high hazard potential. The Probable Maximum Flood is the appropriate spillway design flood. The spillway will pass the 100-year flood (flood having a one percent chance of being exceeded in any year) without overtopping the dam. The spillway will pass 52% of the Probable Maximum Flood without overtopping the dam. The Probable Maximum Flood (PMF) is defined as the flood that may be expected from the most severe combination of critical meteorologic and hydrologic conditions that are reasonably possible in the region.

Lake Timber Ridge 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 hazard to human life or property. Our inspection and evaluation indicates that the spillway does not meet the criteria set forth in the recommended guidelines for an intermediate dam having a high hazard potential. The probable Maximum Flood is the appropriate spillway design flood. The spillways will pass the 100-year flood (flood having a one percent chance of being exceeded in any year) without overtopping the dam. The spillways will pass 14% of the Probable Maximum Flood without overtopping the dam. The Probable Maximum Flood (PMF) is defined as the flood that may be expected from the most severe combination of critical meteorologic and hydrologic conditions that are reasonably possible in the region. Recommendations presented in Section 7 of this report relative to minimizing or eliminating the potential for overtopping of the dam should be pursued on a high priority basis.

This report presents the results of field inspection and evaluation of the Brown Shanty Lake Dam. It was prepared under the National Program of Inspection of Non-Federal Dams. This dam has been classified as unsafe, non-emergency by the St. Louis District as a result of the application of the following criteria: Spillway will not pass 50 percent of the Probable Maximum Flood without overtopping the dam. Overtopping of the dam could result in failure of the dam; and Dam failure significantly increases the hazard to loss of life downstream.

Eastland Lake Dam is an earthfill structure approximately 16 ft high and 800 ft long at the crest. The appurtenant work consists of an earth cut swale at the east abutment and an earth cut channel at the west abutment (initial spillway section). Our inspection and evaluation indicates that the combined spillways do not meet the criteria set forth in the guidelines for a dam having the above size and hazard potential. The combined spillways will pass 36 percent of the Probable Maximum Flood without overtopping. The dam appears to be in fair condition. Deficiencies visually observed by the inspection team were: (1) surface cracking on the crest of dam; (2) some sloughing of the upstream slope; (3) numerous animal burrows; (4) erosion of upstream face of dam (lack of wave protection); (5) trees and brush on slopes of embankment; (6) reported seepage along downstream toe of embankment; (7) trees and brush in west abutment spillway channel; and (8) lack of non-erodible spillway section.