How long will dredging last? When will I have to dredge again?

Dredging projects take a few days up to a year to remove sediment.  A common question before a project begins is “How long will this dredging last?” or “When will I have to dredge again?”  One of the best ways to answer this question is the lake or pond’s history.  How long has it been since the lake was dredged last time or if ever since it was created?  If it was dredged, was there any record of the quantity removed.  The watershed size and characteristics have the most impact on the amount of incoming sediment. Urban areas contribute a lot of stormflow than leads to streambank erosion.  Suburban areas may be continuing to be developed leading to increases in both stormflow and sediment entering the watershed.  A walk up the tributary can tell a lot about the sediment sources.  The best way to track sediment is to perform a bathymetric survey or sediment survey to determine the water and sediment volume at a particular time and repeat the process to evaluate the change.  The amount of sediment and water storage lost can be determined accurately and a plan can be developed based on those facts.  Other options such as remediation efforts or enforcement of best management practices upstream from the lake can be implemented if severe issues are in the watershed.