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2. We support the Water Quality Control Division's requirement that relief from total
<br />suspended solids, total iron, and/or settleable solids should not be granted when the
<br />permittee has control over the discharge (Permit, page 5, I st paragraph). This is because
<br />Colowyo's ponds are designed to treat the 10-year, 24-hour event by allowing that event
<br />to pass through only the ponds' principal spillway inlets, rather than through dewatering
<br />device inlets.
<br />3. It is mentioned that "Outfalls 0026, 0046, 0076, 0086, 0096, and OIOb are not eligible
<br />for (relief from primary effluent limitations) unless the majority of the discharge consists
<br />of surface runoff' (Permit, page 5, first paragraph). It is also mentioned that for WQCD
<br />to waive the primary limitations, it will be necessary for Colowyo to "demonstrate" that
<br />discharge occurred within certain time periods following certain precipitation pond
<br />inflow events. We therefore support the proposed requirements by WQCD that flow
<br />measuring devices be installed for the purposes of making these demonstrations.
<br />4. It is stated in the permit (Page 3, first paragraph) that as long as discharges from Outfalls
<br />001, 002, 003, 004, 005, 006, 007, 008, 009 and Ol0 consist solely of surface runoff
<br />(rather than vehicle washwater or pit pumpage), they must meet the effluent limitations
<br />of Pan I.A.I.a.. It is further stated (Permit, page 5, first paragraph) that discharges from
<br />Outfalls 002, 004, 007, 008, 009, and 010 will not be eligible for relief from the primary
<br />effluent limitations at Part I.A. l.b. (vehicle washwater/pit pumpage) unless the majority
<br />of those discharges consist of surface runoff.
<br />It therefore appears that discharge through outfalls 002, 004, 007, 008, 009, and Ol0 that
<br />are composed mostly of vehicle washwater or pit pumpage will never be eligible for
<br />relief from the primary effluent limitations at Part I.A.I.b., regardless of precipitation.
<br />Is this correct?
<br />It also appears that neither vehicle washwater nor pit pumpage should be discharged
<br />through any outfalls other than 002, 004, 007, 008, 009, and O l0. Is this correct?
<br />5. It is somewhat unclear from the language under "Alternate Limitations" (Permit, pages
<br />3 and 4) when these limitations apply. If, for example, the 6-year, 24-hour event volume
<br />fell over athree-day (72-hour) period, and an associated discharge began three hours
<br />after the rain began and subsequently stopped 80 hours after the rain began, what portion
<br />of the discharge, if any, would be eligible for relief from the primary limitations?
<br />6. It is stated on page 5 (fourth paragraph) of the permit that "If a pond has only manual
<br />dewatering capability, relief is available only to the extent required to regain necessary
<br />stability and capacity". All ponds at Colowyo are required to be designed, constructed,
<br />maintained, and on a quarterly basis, certified by a professional engineer, to contain or
<br />treat certain precipitation event volumes. No pond, therefore, should need to be
<br />dewatered for the purposes of "regaining stability" under normal operating conditions,
<br />as no pond should lose any stability under normal operating conditions. An exception
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