s2ary
09-07-2007, 07:55 PM
Developing new ways of looking at Managing developed watersheds.
More and more we are beginning to recognize and understand the longterm cumulative impacts from the last 20 years of growth. For fisheries it boils down to 3 things;
Thermal Retention; Our water bodies are warming beyond the tolerances of native fish such as brook trout.
Lack of porosity in the landscape; Because of an increase in impervious surfaces, and screen loamed lawns, our landscapes are not allowing precipitation to infiltrate our watersheds and recharge our groundwater supplies. As a result the groundwater volumes and discharge rates into our waterbodies has been reduced. Groundwater discharges at a steady 55 degrees, without these steady cool water discharges and combined with shad-less watersheds our streams and ponds are incapable of sustaining populations of native fish including Brook Trout.
Invasive species degradation of habitats and in to the energy cycle; We have known for a long long time that invasive wetland species severely impact the wildlife values of an area. But we also have come to understand that many of these species, such as Phragmites australis provide low nutrient value detritus back into the watershed. In a study in Barnegat Bay they followed carbon isotopes from Phragmites through the food web into speckled trout. Their conclusion was that the nutrient value of the Phragmites detritus and subsequent food items derived from Phragmites dominated resources was less and more ‘hollow’ than native species resources. It is the equivalent of a Junk Food environment.
Obviously there are other negative influences such as sediments and nutrient loading, but the above three are longterm steady impacts that accumulate over time. Silent killers of the environment. Sediments and nutrients are intermittent impacts that cause obvious visually disturbing impacts that can be quickly addressed. The above three are slow steady killers and take decades to observe and longer to abate.
We are developing a Killer project in Gloucester, Ma that will hopefully be a stepping stone to how we start to look at managing developed watersheds in the future. I can’t hand out any details yet, but as soon as I can I’ll post the whole project outline.
More and more we are beginning to recognize and understand the longterm cumulative impacts from the last 20 years of growth. For fisheries it boils down to 3 things;
Thermal Retention; Our water bodies are warming beyond the tolerances of native fish such as brook trout.
Lack of porosity in the landscape; Because of an increase in impervious surfaces, and screen loamed lawns, our landscapes are not allowing precipitation to infiltrate our watersheds and recharge our groundwater supplies. As a result the groundwater volumes and discharge rates into our waterbodies has been reduced. Groundwater discharges at a steady 55 degrees, without these steady cool water discharges and combined with shad-less watersheds our streams and ponds are incapable of sustaining populations of native fish including Brook Trout.
Invasive species degradation of habitats and in to the energy cycle; We have known for a long long time that invasive wetland species severely impact the wildlife values of an area. But we also have come to understand that many of these species, such as Phragmites australis provide low nutrient value detritus back into the watershed. In a study in Barnegat Bay they followed carbon isotopes from Phragmites through the food web into speckled trout. Their conclusion was that the nutrient value of the Phragmites detritus and subsequent food items derived from Phragmites dominated resources was less and more ‘hollow’ than native species resources. It is the equivalent of a Junk Food environment.
Obviously there are other negative influences such as sediments and nutrient loading, but the above three are longterm steady impacts that accumulate over time. Silent killers of the environment. Sediments and nutrients are intermittent impacts that cause obvious visually disturbing impacts that can be quickly addressed. The above three are slow steady killers and take decades to observe and longer to abate.
We are developing a Killer project in Gloucester, Ma that will hopefully be a stepping stone to how we start to look at managing developed watersheds in the future. I can’t hand out any details yet, but as soon as I can I’ll post the whole project outline.