Holistically Analyzing the Benefits of Green Infrastructure - Guidance for Local Governments
The University of Maryland’s Environmental Finance Center developed this document for smaller, local governments with municipal separate storm sewer systems (MS4) to evaluate the co-benefits of implementing green infrastructure (GI) in response to stormwater regulations. The report includes a discussion of measurement and valuation of GI benefits, and recommends using the triple-bottom-line framework (environmental, social, economic) to assess the value of GI. Green infrastructure offers many benefits to climate adaptation and resilience which are detailed in this report, such as flood mitigation, water supply augmentation, heat island mitigation, and public health benefits.
Following a general overview of GI for stormwater management, the range of GI benefits are described in terms of water quality and quantity, air quality, habitat and wildlife, and people and communities. All of these advantages support a more climate change adaptive environment, for example:
Heat Island Mitigation: GI introduces vegetation that provides shading and evaporative cooling that can mitigate the heat island effect. The resulting lower ambient temperatures lead to lower energy use for cooling, and reduced hospital visits and other heat-stress related health effects.
Flood Mitigation: GI practices mitigate flood risk by reducing the amount of impervious surface, and establish vegetation that can slow the flow and volume of stormwater runoff. The benefits of flood mitigation can be valued one of three ways: avoided costs of clean up and/or repair, changes in flood insurance premiums, or impact on property values.
Water Supply: GI practices offer two pathways to benefiting water supply - through rainwater harvesting and reuse or groundwater recharge.
Health Effects and Benefits: Improved air quality from greening can reduce the risk of health impacts ranging from asthma to premature mortality. Increased presence of green infrastructure also contributes to improved mental and physical health outcomes.
Five ways to consider GI benefits for a holistic assessment to support decision-making and implementation are identified:
- Cost-effectively achieving regulatory compliance: direct benefits and cost-effectiveness drive the decision process
- Community engagement: GI practices often rely on an engaged community to assist with siting and post-installation monitoring and maintenance
- Addressing under-serviced communities: social and economic co-benefits of GI can provide added value and assets to underserved communities
- Motivating collaboration: understanding the strength of co-benefits across private, public and nonprofit sectors through the triple-bottom-line framework can help engage partnerships
- Pursuing grant funding: articulating co-benefits can help make a more compelling case for competitive grant funding
The table entitled “When to monetize benefits” offers guidance on characterizing, quantifying, and monetizing direct and co-benefits of GI. Three case studies are provided at the end of the document to illustrate how evaluating direct and co-benefits of GI can inform decision making and stakeholder engagement.
Publication Date: October 2017
- Best practice
- Case study
- Air quality
- Precipitation changes
- Water quality
- Water supply