Darlington County, SC Environmental Rules: Erosion Control (2026)

Section 5.6(H) of the Development Standards Ordinance, Appendix A, requires grass seed to be established by hydroseeding, sod mats, or hand seeding with mulching whenever graded earthen slopes exceed 4:1 (four horizontal to one vertical), or wherever the county determines erosion risk is significant. The hydroseeding method must follow SCDOT Standard Specifications Section 810.18 using Method C wood cellulose fiber tackifier. Seasonal seed rates are set precisely: seeding done August 15 through March 1 must use 90 pounds per acre of unhulled common bermuda plus 30 pounds per acre of annual rye grass, while seeding from March 1 through August 15 must use 60 pounds per acre of hulled common bermuda plus 50 pounds per acre of brown top millet.

Fertilizer must be applied at 1,000 pounds per acre of 10-10-10 and agricultural lime at 2,500 pounds per acre. The resulting stand of grass must meet SCDOT Standard Specifications Section 810.13. Where longitudinal slopes exceed five percent or drainage works show excessive siltation, the county can require additional measures such as silt fences, riprap, piping, or silt dams, all subject to county approval before installation. This erosion control duty sits within the broader drainage standards of Section 5.6, which also makes the developer responsible for any damage to drainage facilities during construction and for two years of storm drain maintenance liability after county acceptance, or until 80 percent of the lots have sold.