What We Do
Combined Sewer Overflow Model Predictions
CSOs should only occur during wet weather. Whether an overflow occurs and its magnitude depends on many factors including rainfall volume, rainfall intensity, whether it has rained in previous days. CSOs typically overflow more in wet years than dry years. More intense rains also make it more likely that CSOs will occur.
Yearly Predictions
Download a summary, based on computer modeling, of overflow events in an average year with typical rainfall (PDF 58 kb) . For each CSO, the document summarizes:
- Number of overflows
- Total overflow volume
- Estimated minimum rainfall volume necessary to cause an overflow
- Average duration of overflow.
Prior Quarter CSO Predictions
DC Water uses its computer model of the combined sewer system to predict the actual CSOs that have occurred in the prior calendar quarter. The most recent CSO prediction results (PDF 11 kb) are available for download.