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  <br />2  <br />  <br />“Monitoring Program” section of the report (bottom of page 4), Chesney explains that later <br />when the system is in use and being monitored, having the water samples tested by a certified <br />laboratory will satisfy the requirement for system certification. This is not what the State <br />Policy says or means. Third party certification/testing to document the validity of the system <br />must occur before it can be considered and approved for use. There are many commercially <br />available systems that have gone through NSF or other testing/certification programs that <br />could be used for this project. There is nothing preventing the designer from seeking similar <br />third-party testing and certification for this system to verify the merit and demonstrated <br />performance of this design. <br /> <br />2. Inadequate Leaching Capacity. While the proposed design is may be an effective way of <br />promoting vegetative uptake of nitrogen, it fails to provide the necessary leaching capacity <br />for the 4-bedroom residence it will serve. The design proposes to use (9) 35-ft long lengths of <br />12-inch diameter EZflow drain modules spaced 2-ft apart; the space between the modules <br />will be packed with native soils. The infiltrative area beneath the EZflow modules totals 315 <br />ft2 (9 x 1’ x 35’), which is all that can be credited as leaching area; the areas backfilled with <br />soil between the modules cannot be considered effective leaching area. Multiplying 315 ft2 <br />of leaching area times the application rate of 0.686 gpd/ft2 cited in the design report gives a <br />total leaching capacity of 216 gpd, which is well short of the standard of 560 gpd for a 4- <br />bedroom house (based on 140 gpd per bedroom). On page 5 of the design report, Chesney <br />claims a leaching capacity of 600 gpd, based on 0.686 gpd/ft2 applied to the overall <br />dimensions of the excavated bed (25’ x 35’= 875 ft2). Chesney includes credit for 560 ft2 of <br />area backfilled with soil, which is not supportable by any code, studies or industry practice <br />that I am aware of. As a result, the proposed design provides inadequate leaching capacity <br />and would have to be nearly tripled in size to meet the leaching capacity requirements for a <br />4-bedroom house. <br /> <br />3. Other Design Issues. There are other design issues that would also have to be addressed if <br />the comments in 1 and 2 above can be resolved, as follows: <br /> <br /> Clogging of EZflow. The EZflow drain modules specified come with a half-section of <br />filter fabric secured over the top, and the lower half open for dispersal of effluent into the <br />adjacent native soil. The proposed design will backfill with loose soil around the entire <br />module with the additional intent of encouraging roots to extend around and into the <br />EZflow aggregate. This poses a serious risk of soil and root intrusion and potential <br />clogging of void spaces within the geosynthetic aggregate. The designer should provide <br />technical review and concurrence of this proposed application of EZflow drainage <br />modules from the manufacturer, specifically addressing the risk and possible <br />consequences of clogging by soil and/or root intrusion. <br /> <br /> Equal Effluent Distribution. Based on the design rationale, the system is highly <br />dependent on effluent being spread equally over the entire leaching-filter bed in order to <br />support a uniform growth of fescue grass over the entire bed. Vegetation management <br />and the theoretical projections of nitrogen uptake rely on uniform effluent dispersal. <br />Gravity piping systems, such as that proposed, are susceptible to the development of