Virginia Administrative Code › Title 12 - HEALTH › Agency 5 - DEPARTMENT OF HEALTH › Chapter 640 - ALTERNATIVE DISCHARGING SEWAGE TREATMENT REGULATIONS FOR INDIVIDUAL SINGLE FAMILY DWELLINGS › Part II - Procedures › Section 12VAC5-640-400 - Classifications of discharge points

Current through Register Vol. 40, No. 24, July 15, 2024
The nature of the discharge point will determine what
					 precautions must be taken to protect public health and environmental
					 resources.
1. Where an all weather
				  stream is available, it shall be used rather than discharging to an
				  intermittent stream, dry ditch, or wetland. An all weather stream can readily
				  dilute the effluent at least 10:1 at the seven consecutive day average of a
				  10-year low flow (7-Q-10) and thereby minimize public health and water quality
				  impacts.
2. An all weather stream
				  is represented by a solid blue line on the most recently published 7.5 minute
				  United States Geologic Survey topographic map and has a 7-Q-10 flow that can
				  provide 10:1 dilution of the effluent. Intermittent streams are represented by
				  a dotted and dashed blue line on the most recently published 7.5 minute United
				  States Geologic Survey topographic map. An all weather stream that provides
				  less than 10:1 dilution of the effluent based on 7-Q-10 flow shall be
				  considered an intermittent stream. Intermittent streams and dry ditches have an
				  assigned stream flow 7-Q-10 of zero.
3. An owner may submit to the division
				  additional hydrologic data, including but not limited to stream records and
				  anecdotal evidence of long time residents, to support that a stream can provide
				  a dilution ratio of 10:1. When in the opinion of the division, the evidence
				  warrants a change, the division may determine that a stream is an all weather
				  stream for the purposes of this chapter. The owner may also request site
				  specific stream flow determinations from the Department of Environmental
				  Quality.
4. Discharges into
				  intermittent streams or dry ditches that do not have the dilution capability
				  cited in subdivision 1 of this section shall be located entirely within the
				  owner's property, or within a recorded easement as described in subdivision 2
				  of 12VAC5-640-450.
a. The average slope for any intermittent
				  stream or dry ditch discharge receiving effluent from a discharging system
				  shall be a minimum of 2.0% for the first 500 feet from the point of discharge.
				  The intermittent stream or dry ditch shall be protected from erosion by the
				  discharge as needed.
b. In order to
				  prevent ponding, the minimum slope shall not be less than 1.0% at any
				  point.
c. All slope measurements
				  described in subdivisions 1 and 2 of this section shall be made prior to
				  initiating any grading and are intended to reflect naturally occurring swales
				  and drainage ways. Nothing contained herein however, is intended to prohibit a
				  property owner from making minor grading improvements to prevent ponding in
				  areas with minimal slopes. Naturally occurring swales and drainage ways may be
				  extended with an engineered channel on a case-by-case basis, but any engineered
				  channel must tie into the existing natural swale or drainage.