07/25/2007 Env Bd Packet - Laserfiche WebLink

Home Search

• Conversely, increased runoff volume means decreased infiltration of water into the soil and groundwater. Groundwater baseflow supports drinking water sources and the function and value of groundwater- dependent natural resources. Percolation through soils also allows natural systems to remove pollutants from groundwater that may be withdrawn for use or that ultimately will emerge in surface waters. The most substantial proposed changes are directed largely toward protecting the integrity of the groundwater system. B. Applicability The stormwater rule would be reorganized to be more readily understandable. Instead of a simple clause applying the permit requirement broadly, with substantial exceptions at the end of the rule, the proposed rule would more carefully define permit applicability up front and reduce the exceptions section substantially (Section 2). The applicability section would specifically define the permit requirement for residential, commercial and industrial development and redevelopment. The rule would continue to apply to other forms of land disturbance (including roadways and trails) through the broad introductory clause. Two substantive changes would be made to the permit applicability language: • Presently, industrial, commercial or multifamily residential development on a site smaller than 2.5 acres is exempted from the rule unless it is near a floodplain or specified waterbody. The proposed rule would reduce the scope of this exemption so that it would apply only to development on a site smaller than one acre (Paragraph 2(a)). The exception from the permit requirement for single - family residential development would remain for sites smaller than five acres (Paragraph 2(b)). • In the case of site redevelopment where less than 50 percent of the site is being disturbed, the present requirement to detain and treat the 2.5 -inch storm within a basin applies only to that part of the site being disturbed. The rule proposes to change this, so that the detention /infiltration requirement will apply to all site hard surface if the proposal either (a) would disturb 50 percent or more of existing hard surface or (b) would increase hard surface by 50 percent or more (Paragraph 2(e)). However, while the additional hard surface would be subject to 6