LID is a toolbox of site-scale practices that the site designer and developer can utilize to:

• manage urban rainfall where it occurs for minimized stormwater concentration and runoff
• potentially lower short-term and long-term development costs
• improve water quality
• enhance natural habitat and flood control
• improve green space aesthetics and potentially increase property values
• increase community quality of life and livability

There are many practices that are used to support these benefits, including bioretention systems, rain gardens, vegetated rooftops, bioswales, rain barrels, and permeable pavements to name a few. By implementing LID principles and practices, water can be managed in a way that reduces the impact of built areas on the environment while providing numerous additional benefits. (source: LID symposium).

This concept is very similar to NWRM in the United States context. It is very connected to Green Infrastructure. See also the link to US EPA green infrastructure website.

Water retention covers a wide set of mechanisms (see synthesis document n°1) the effect of which are to increase the capture of water by aquifers, soil, and aquatic and water dependent ecosystems.
More precisely it refers to capabilities of catchments (including wetlands, rivers and floodplains but also other land areas) to hold or retain as much water as possible during periods of abundant or even excessive precipitation, so that water is available for use during dry periods and runoff peaks are minimized.

Areas that are inundated by surface or ground water with frequency sufficient to support a prevalence of vegetative or aquatic life that requires saturated or seasonally saturated soil conditions for growth or reproduction.
Wetlands provide both stormwater attenuation and treatment, comprising shallow ponds and marshy areas covered in aquatic vegetation.ﾠ Wetlands detain flows for an extended period to allow sediments to settle and to remove contaminants.ﾠ They also provide runoff attenuation and can provide significant ecological benefits.