A mulch is a layer of material applied to the surface of an area of soil. Its purpose is any or all of the following:·       to conserve moisture·       to improve the fertility and health of the soil·       to reduce weed growth·       to enhance the visual appeal of the areaMulching as NWRM is using organic material (e.g. bark, wood chips, grape pulp, shell nuts, green waste, leftover crops, compost, manure, straw, dry grass, leaves etc.) to cover the surface of the soil. It may be applied to bare soil, or around existing plants. Mulches of manure or compost will be incorporated naturally into the soil by the activity of worms and other organisms. The process is used both in commercial crop production and in gardening, and when applied correctly can dramatically improve the capacity of soil to store water.

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.