Climate Change and Stormwater Management in the Lake Champlain Basin: An Adaptation Plan for Managers
The effects of a changing climate have been and continue to be observed in the Lake Champlain Basin. Since the 1970s, there have been notable increases in air and lake temperatures, with the rate of increase progressing more quickly over time. Also since the 1970s, lake water levels have risen due both to land use disturbances and more regional precipitation (Stager and Thill, 2010). In winter, the number of days the lake is covered with ice is decreasing, while the number of days above freezing each year steadily rises. Increasingly, climate models suggest a future with more frequent and intense storm events, more precipitation as rain and less snow in the winter (Frumhoff et al., 2007; Horton et al., 2014). These changes lead to a warmer, wetter future with nearly year-round rainfall. Water resource managers must be prepared for these changes.
When rainfall enters a landscape, water percolates through natural surfaces, is retained on the surface and evaporates, or runs directly into waterways. Much of the time, especially with large events, the majority of precipitation ends up as runoff, or stormwater. Management of this runoff aims to reduce pollution and prevent damage from flooding. However, more frequent and intense storm events in the future could lead to higher runoff volumes and more pollutants entering our waterways. As more land is developed in the Lake Champlain Basin, use of improved stormwater management practices has never been more critical. Currently, both Vermont and New York have some management standards in place that account for predicted changes in climate as well as mitigation strategies for more frequent floods. But the current management standards are limited to addressing the first inch of rainfall in a storm event, and providing flow control determined by historical rainfall records. As storm events become larger and more frequent due to climate change, these state-wide management standards must be updated to accommodate. In addition, implementation of climate-ready stormwater management on the ground is lagging and it is important to understand why. Following the flood events of 2011, many municipalities found they were unprepared. And, though legislative efforts intended to curb poor management were put in place, some communities continue to build within floodprone areas, improperly maintain stormwater systems, and install undersized infrastructure. Improved stormwater management techniques including the incorporation of green infrastructure and the proper sizing of grey infrastructure, along with education and outreach to municipalities and property managers, is needed throughout the basin. Policy and funding changes that prioritize low-impact development can be the difference between a climate resilient community and one that must rebuild after every flood event.
In light of a changing climate, sound stormwater management adaptation strategies can preserve and strengthen the health of Lake Champlain and its watershed. Working together across the municipal, regional, state and federal levels facilitates the implementation of more effective management strategies. Though the region may feel the effects of a warmer, wetter climate, preparing now for potential flood events can prevent widespread damage to infrastructure and homes and reduce pollution to waterbodies.