Comment submitted by Debra Wright-Hughes, P.E., Senior Professional Engineer, Marbach, Brady & Weaver, Inc.

Comments on Proposed Stormwater Effluent Rules 1. One fundamental issue is the matter of regulating flows that actually leave a site for the 2 year storm flow. In my area of Northern Indiana, our soils are largely sandy in nature. This allows stormwater flow to be retained on site, without overflow to streams, lakes and ditches in the area. This stormwater is filtered through the soil and enters the groundwater system. The natural filtering process of water through soil removes sediment from the water. This means that rules such as this that regulate effluent from the site do not apply. There is no stormwater leaving our sites by surface flow. Despite this, our local County Soil and Water Conservation Service regulates these sites just as if the flow was actually leaving the site by surface flow. This is fundamentally wrong, and is misapplication of the law. If stormwater flow remains on the site, then the site owner will logically work to stabilize the soils and minimize erosion on their own site. The owner can be required to show that all storm water remains on the site up to the 100 year storm. Then, the owner should be released from any further regulation for erosion control. This point is missing from all of this documentation and needs to be included and made clear to all the regulators. 2. The cost-benefit analysis of the three Options is fundamentally flawed. In order for something to be implemented as beneficial, the benefits must outweigh the cost. None of the three Options offer more benefit than cost. The ratio of benefit to cost is 1:10 at best and 1:12 at worse. I fundamentally disagree with imposing regulation that is 10 times as expensive as the benefits it is designed to yield. Much less costly options must be implemented that yield a positive ratio of benefit to cost of 1:1 at minimum. 3. These comments refer to the proposed rules for stormwater flow that actually leaves a development site. a. Porous baffles developed by the North Carolina DOT should not be a minimum requirement for all sediment basins. Local jurisdictions should be allowed to develop their own practices. The porous baffle should be an option, but not a requirement. b. Detention time requirements should be one of the criteria for sediment basin design, along with overflow rate. c. Specific soil particle size removal should not be a requirement of the new rules. Some clay soils are impossible to completely settle in a sediment basin. Detention time and overflow rate are more reasonable measures of sediment removal. d. Sediment basins should be designed to match pre-development conditions to minimize impact on downstream watersheds. e. Option 1: The minimum size for a site to require a sediment basin should be 20 acres or more, with flow from the stormwater storage system that actually leaves the site by surface flow. The reason for this is that a site of 10 acres will have to use 10% of the site for sediment control. This is not reasonable, and imposes a harsh burden on the property owner. This burden is in addition to parts of the site already dedicated for stormwater retention purposes. A larger site has more flexibility on the use of land, and the use of 5% of the property for sediment control temporarily during construction is more reasonable. Thank you for your consideration of my comments. Debra Wright-Hughes, P.E. Senior Professional Engineer Marbach, Brady & Weaver, Inc. 3220 Southview Drive Elkhart, IN 46514 debra@marbachpls.com