A state revolving fund (SRF) is a fund administered by a U.S. state for the purpose of providing low-interest loans for investments in water and sanitation infrastructure (e.g., sewage treatment, stormwater management facilities, drinking water treatment), as well as for the implementation of nonpoint source pollution control and estuary protection projects. An SRF receives its initial capital from federal grants and state contributions. It then emits bonds that are guaranteed by the initial capital. It then "revolves" through the repayment of principal and the payment of interest on outstanding loans. From Wikipedia
