Hopefully as you’re reading this the April showers
that jump to mind are warm spring rains and not late-season snowstorms. (With
the number and severity of snowstorms that have blanketed much of the U.S. this
past year, it’s hard to tell.)
Unpredictability in weather duration, frequency, and
severity is a good segue into how green infrastructure can benefit utilities.
Whether the flows are from snowmelt, gentle soaking spring rains, or deluges
from summer thunderstorms, incorporating natural systems can help extend the
life and effectiveness of existing gray infrastructure solutions.
When it comes to stormwater control and treatment,
green infrastructure can reduce the effect of nonpoint sources and achieve cost
savings, especially in areas with combined sewer systems. This is the case in
Lancaster, Pa., where the combined sewer system can’t keep up with the area’s
growth as well as intense rainstorms and other wet weather events. Because
Lancaster’s waters flow into the Chesapeake Bay watershed, the city faces extra
pressure to control its discharges.
Given the expense of gray infrastructure
modifications, the city has instead opted for a two-pronged strategy to reduce
the volume of CSOs: increase the efficiency of the city’s existing gray
infrastructure, and employ green infrastructure stormwater management methods. Find out how Lancaster is seeking to become a model example of the application of the integrated municipal planning and green infrastructure promoted by the U.S.
Environmental Protection Agency beginning last October.
But green infrastructure and natural systems can do
more than just help with wet weather issues. They also can help move the water
quality needle, as the Sanitation District No. 1 of Northern Kentucky (SD1) has
discovered. While SD1’s story stems from a consent decree to control wet
weather, the decree fosters “integrated watershed management to make real
improvements in water quality at times when the improvements would most benefit
potential users of local water resources,” according to the article.
Instead of focusing solely on preventing pollution
from reaching the waters, SD1 created a pilot wetland system to reduce bacteria and nutrient loads from a local creek during most flow conditions. In its first
year, the pilot project, which is pictured on the cover, successfully reduced
total suspended solids, orthophosphate, and bacterial concentrations. While
these preliminary results should not be considered conclusive, the article
says, they do provide encouragement that a watershedwide management approach
could meet water quality objectives and that this approach could be more
cost-effective than traditional gray infrastructure overflow controls alone.