1. Disconnected Drain Spout - Rain water begins to pool as ground reaches saturation and water flows along surface.
2. Topsoil is saturated excess runs off towards the sidewalk.
3. Rock pit fills and the excess water flows into the storm sewer.
4. Perforated pipes allow some of the water to seep into the soil reducing the amount that needs to be drained.
5. Drainage swales overflow as subsurface gets saturated.
6. Trees drink significant amounts of water reducing the amount of water that needs to be drained.
7. Water reaches the settling pond where it can soak into the ground or evaporate. The ponds provide a buffer for flows to the creek.
8. Creek Floods on long heavy rainfall similar to undeveloped conditions and long term water flows are provided by groundwater.