7 Del. Admin. Code § 7401-8.0

Current through Reigster Vol. 28, No. 6, December 1, 2024

Section 7401-8.0 - Criteria for Low Flow Waters

8.1 A low flow water is one in which the 7Q10 freshwater inflow is less than 0.1 cfs. The following criteria shall apply to discharges into low flow waters:

8.1.1 Where information is available for the receiving water which indicates that, because of low flow, it would not support designated uses, then numeric criteria shall not apply. The numeric criteria shall then apply at the closest downstream point where uses could reasonably be expected to occur.

8.1.2 The discharge shall not add:

8.1.2.1 Materials which result in the accumulation of toxic substances in sediment, aquatic life or food chains at levels that may be harmful to the health of humans or aquatic life;

8.1.2.2 Materials in concentrations that may settle to form deposits which smother benthic organisms, may exert significant dissolved oxygen demand, or may create a nuisance condition;

8.1.2.3 Floating debris, oil, scum, foam, and other matter in concentrations that may cause a nuisance condition;

8.1.2.4 Substances in concentrations that produce color, odor, taste or turbidity that may lead to significant disruption of a public water supply treatment systems, or may cause a nuisance condition; or

8.1.2.5 Substances in concentrations that may result in a dominance of nuisance species, or may affect species diversity.

8.2 The applicant for discharge shall bear the burden of showing, to the satisfaction of the Department, that the provisions of subsections 8.1 .1 and 8.1.2 above are met.

8.3 Any application for new or increased discharge to a low flow water must include a thorough evaluation of alternate discharge configurations, including but not limited to water conservation, relocating the outfall to a more suitable location, conveying the wastewater to other available treatment facilities, or utilizing land treatment. Alternatives which do not include discharge must be used wherever technologically feasible and cost-effective (notwithstanding other requirements of these or other applicable regulations).

7 Del. Admin. Code § 7401-8.0

21 DE Reg. 241 (9/1/2017) (Final)