Dams, Standpipes, Bank Integrity and Safety Concerns

Water levels in most ponds in Chester County are controlled by standpipes, capable of preventing excessively high water levels during rainfall events but incapable of regulating minimum water levels during droughts. A frequently-encountered problem in older ponds is corrosion of the standpipe, often leading to persistently low water levels and erosion of exposed bank sediments. A small expenditure in fixing an old standpipe can delay the much larger expense of dredging eroded sediments from the pond basin.

sechi meter

Rusted standpipe at a pond in West Brandywine Township.

Standpipes with bottom withdrawal capability are a very helpful feature in allowing water levels in the pond to be drawn down, as is sometimes required for shoreline erosion control projects, removal of aquatic plants, or the removal of fish. If a standpipe needs repair, addition of a bottom withdrawal valve should be considered.

When water levels are controlled by an earthen dam, inspection and any needed maintenance of the dam should be, at a minimum, an annual event. Unlike most of the shoreline, the dam should be maintained as mowed grass. Trees and shrubs are best kept off of the earthen dam embankment as the root systems will reduce the strength of the dam and its ability to hold the water in the pond. Any damage caused by burrowing animals (e.g., groundhogs) should be repaired on a regular basis for the same reason.

storm breach

A major storm breached the berm of this pond in East Marlborough Township, resulting in large and unplanned repair costs.

For larger ponds, whether the water level is controlled by a dam or standpipe, there should be a carefully maintained overflow spillway near the outlet of the pond. Spillways may consist of mowed grass or be constructed using cement or rock riprap. Further information is available on-line from PA Department of Environmental Protection - Bureau of Waterways Engineering - Dam Safety Division.