Impact Bond: DC Water Environmental Bond
Stage of development: Implementation
Policy sector: Agriculture and environment
Social challenge: Stormwater runoff
Intervention: Development of green infrastructure (i.e. permeable pavement and bioretention) designed to mimic the same absorption and filtering processes found in nature in order to slow surges of stormwater during periods of heavy rainfall. Beneath the surface of a rain garden or permeable pavement installation, there are layers of soil, rock, and gravel that slowly filter stormwater allowing it to be reabsorbed into the ground or flow into the sewer system and back to the treatment facility for treatment. By absorbing and slowing stormwater, green infrastructure mitigates stormwater runoff, ultimately reducing the incidence and volume of CSOs (i.e. Combined Sewer Overflow).
Date outcomes contract signed: 2017
Start of service provision: 2016-10
Total investment commitment currency: USD
Total investment commitment: 25000000
Total investment commitment (USD): 25000000
Maximum potential outcome payment: 28300000 USD
Maximum potential outcome payment (USD): 28300000
Target population: 20 equivalent impervious acres of green stormwater infrastructure for Rock Creek Project A.
Notes: The cost of installing the green infrastructure are paid for by DC Water (through the issuing of a 30 year municipal tax-exempt bond with a mandatory term of 5 years), but the performance risk of the green infrastructure in managing stormwater runoff is shared amongst DC Water and the investors through the SIB mechanism. Only a 3,3 million USD payment is linked to performance metrics.