In a natural Virginia
woodland or meadow, very little
rainfall runs off the land. During development of land natural vegetation is
usually removed and replaced with hard surfaces such as roads, buildings,
parking areas, lawns or playfields, etc. -- all where forests once stood.
This land surface change decreases infiltration, groundwater recharge and
evapotranspiration and it increases runoff -- often dramatically. During
the past 20-30 years conventional strategies for managing stormwater runoff from
developed land included a major emphasis on draining all the runoff from the
site (roofs, roads, lawns, etc.) to the lowest spot on the property, building an
engineered pond to capture it and then regulating the release to the nearest
stream. Although this worked to some degree, it did have limitations including
too much water released to a receiving stream thereby causing channel and
streambank erosion, total loss of any groundwater recharge and little if any
water quality treatment to remove pollutants from the runoff from developed
More current times place a strong emphasis on Low Impact
Development (LID) which emphasizes maintaining the pre-existing hydrology
(runoff and infiltration pattern) on a site after the site is developed. This
places a stronger emphasis on intercepting, infiltrating and capturing water on
the site rather than just sending it downstream.
There is a rapidly growing focus on LID strategies and
practices. At the same time there is a rapidly approaching deadline,
July 1, 2014,
for local governments to adopt local stormwater management programs which
require adoption of all new state stormwater regulations in Virginia. These new
regulations embrace much of the concept of Low Impact Development.
Changes in stormwater management programming in
Highland County will be a topic of a great degree of focus for the next
fourteen months and beyond.