Understanding how land use patterns affect water runoff and flooding is vital to developing policy on how to manage stormwater within a watershed. Now, for the first time, researchers at the University of Massachusetts at Amherst have taken continent-wide information from satellites, field stations and USGS stream gauges across the US and tied that to runoff.
It’s no surprise that data shows runoff is highly variable across the US. The primary drivers of that variation include temperature, evaporation, precipitation, soil moisture, vegetation and watershed size. Green infrastructure such as bioswales and rain gardens are good for some locales and retention basins in others. Urban forestry is a vital aspect of green infrastructure in almost all watersheds.
Green infrastructure design can successfully manage runoff, the authors state, adding that incentives could be developed based on models for individual watersheds. For instance, if the watershed is influenced by evaporation, a city could incentivize green infrastructure that facilitates infiltration. If the watershed is dominated by high precipitation events, incentives could be put in place to manage and reduce runoff, such as bioswales and rain gardens. For Southwestern watersheds that are influenced primarily by temperature and soil moisture, encouraging retention basins and native vegetation may be helpful.
“We also want to highlight the importance of natural systems such as forest cover and open space when a town is considering new parking lots or shopping centers, for example. You can’t just take away such ecosystem services and expect everything to be OK,” said author Dr. Timothy Randhir, in a University of Massachusetts, Amherst press release. “In the past the problems just flowed away to become some other town’s problem, but that isn’t going to work anymore.”
A new analysis and approach to watershed management. Watershed scientists offer national flood and runoff assessment on ScienceDaily.
Effect of climate and land cover changes on watershed runoff: A multivariate assessment for storm water management, by Paul Ekness and Timothy O. Rankhir in an early online edition of Journal of Geophysical Research: Biogeosciences, 120, doi:10.1002/2015. http://onlinelibrary.wiley.com/doi/10.1002/2015JG002981/full