This study presents an overview of investigations on impact of small detention ponds (low-volume reservoirs, located in urban areas) on suspended sediment removal. Not only solids but also other pollutants are trapped in reservoirs, mainly heavy metals and phosphate compounds. Trapping is more efficient in case of wet detention ponds than dry detention ponds. In order to ensure expected functions of detention ponds, regular maintenance and inspections are required. A conceptual model is considered as a tool, which can be used to estimate trap efficiency of a detention pond. It treats a reservoir as if it was a single continuous stirred tank reactor. The model can be characterized with a low number of parameters and a simple structure, which is useful in case of ungauged catchment.