Section 12-6-3370 of the 1976 South Carolina Code of Laws provides for a state tax credit for the construction, installation or restoration of water impoundments and water control structures used for certain purposes. That Section of the 1976 Code is printed here:

Section 12-6-3370. Tax credits for construction, installation or restoration of water impoundments and water control structures.

1. A taxpayer may claim a credit for twenty-five percent of all expenditures for the construction, installation, or restoration of ponds, lakes, other water impoundments, and water control structures designed for the purposes of water storage for irrigation, water supply, sediment control, erosion control or aquaculture and wildlife management, providing these items are not located in or adjacent to and filled primarily by coastal waters of the State.
2. In the case of pass-through entities, the credit is determined at the entity level and is limited to two thousand five hundred dollars. The maximum amount of credit for all taxpayers, including any credit passed through to the taxpayer from a partnership, "S" Corporation, estate, or trust, is also limited to two thousand five hundred dollars.
3. If the credit exceeds the taxpayer's tax liability for the taxable year, the excess amount may be carried forward for credit against income taxes in the next five succeeding taxable years.
4. To qualify for the credit the taxpayer must obtain a construction permit issued by the Department of Health and Environmental Control or proof of exemption from permit requirements issued by the department, the Natural Resources Conservation Service, or a local Soil and Water Conservation District.

To obtain the proof of exemption form referenced in (D) above, the owner must first insure that the dam is less than 25 feet high and will impound less than 50 acre feet of water and does not present a hazard for loss of life in case of failure (for dams of lesser size). Once the owner has determined with certainty that his dam does not meet the size requirements to require a permit, proceed with construction. When construction is complete, call the DHEC Environmental Quality Control Regional Office of the county in which the dam is located, and ask for the Dam Certificate of Exemption Form. The Regional Office will arrange for someone to meet the owner or his representative at the dam to verify its location, size, and use. That Regional Office representative will issue the Certificate to the owner, and the owner can then use that document to apply for the tax credit when he files his state income tax return on or before the following April 15th. For permitted dams, the permit to construct and certificate of completion should be filed with the state income tax return.