Brief Summary of “Conservation Design for Subdivision, A Practical Guide to Creating Open Space Networks” by Randall Arendt 
 

50% of buildable land may be conserved on any development by grouping new development in a more compact, efficient and neighborly manner without reducing overall density or profitably.
 

Identifying open space areas to protect.

Primary Conservation Areas
1) Unbuildable wetlands
2) Water bodies
3) Floodplains
4) Steep slopes 25% or greater

Secondary Conservation Areas
1) Mature woodlands
2) Upland buffers around wetlands and water bodies
3) Prime farmlands and forest lands 
4) Natural Meadows
5) Critical wildlife habitat
6) Sites of historic, cultural and archaeological significance
 

The Process

Remove unbuildable areas from total acres.  Now determine total number of lots based on acreage of secondary conservation and other buildable  acreage.  (Density Neutral) Now cluster this number to save secondary conservation areas.

Up to ½  area of the buildable area (secondary conservation and other buildable areas) can be subdivided for residential, the balance of buildable remains undivided open space.  Of this protected open space, ½ could be left natural and ½ developed for active, formal recreation such as parks, ball fields, etc.

Another simplified explanation is remove non-buildable acres, 
then within the  buildable area, 
¼  is undisturbed open space
¼  is modified open space for active recreation
½  is developed as residential, at twice the normal density.  Note the percentages can very depending the desires of the community
 

Summary of steps

1) Identifying all potential conservation areas
2) Locating house sites
3) Designing street alignments and trails
4) Drawing lot lines

Environmental and Ecological Benefits

1) Protect upland buffers along wetlands, water courses and  water bodies
2) Wildlife corridors
3) Filter stormwater flowing to ponds, lakes and rivers
4) Trap nutrients and pollutants from stormwater
5) Slows stormwater velocity which reduces erosion
6) Cooling effect for wildlife, water and homes
7) Buffer width for residential – 100 feet @ 8 percent slope
8) Connect riparian woodlands as corridors

Developing Area-wide map of conservation and development areas

1) Wetlands
2) 100 year floodplain
3) Steep slopes 25% or greater
4) Habitats of species that are endangered, threatened, or significant, unique or special areas
5) Historic, archaeological or cultural sites listed on “National Register of Historic Places” or state or local inventories.
6) Active farmland and forestland rated as prime or state-wide importance
7) High yielding aquifers and recharge areas
8) Woodlands of a size locally significant or mature woodlands one or more acres in size.