Laserfiche WebLink
February 27, 1998 <br />WQCD Letter <br />Page 3 <br />With regard to when the 48 hour "clock" should start, we believe the "start times" <br />proposed in the draft WQCD permit are appropriate. For rainfall events, a "clock" <br />could be started when the event starts. However, this would be somewhat unfair to <br />Colowyo in that a significant portion of the 48 hours could elapse before the runoff <br />associated with the event would reach a sedimentation pond. For rainfall events, the <br />clock could also be started a few days after the event stops. However, the majority of <br />the more sediment-laden slug of water would probably enter and leave the pond <br />before then. As this slug of water would still have to meet primary limits (as the <br />"clock" of alternate limits hadn't yet gone into effect), this would also seem <br />potentially unfair to Colowyo. We believe that for rainfall events, starting the 48 <br />hour clock when a rainfall event ceases is the most appropriate time. <br />For snowmelt, it would seem more fair to Colowyo to allow the "clock" to start at a <br />later time than for rainfall events. While rainfall-based inflow may reach a pond <br />within a few minutes to within a few hours, it could be days before snow from a <br />particular snowfall event actually melted into surface flow. It would therefore be <br />more fair to a Colowyo to delay the start of the clock to when pond inflow ceases (as <br />proposed) rather than when snowfall ceases (as proposed for rainfall events). <br />We have an additional comment with regard to this item, If the 48 hour clock for <br />snowmelt starts when pond inflow from snowmelt ceases, does this mean that any <br />discharge that occurs before pond inflow ceases needs to primary limits? <br />6. WQCD did not elect to respond to our comments. Colowyo, however, in its <br />February 9, 1998 letter did. Colowyo commented that it agrees with DMG's January <br />12, 1998 comment that no pond should need to be dewatered for the purpose of <br />regaining stability under normal operating conditions, as no pond should lose any <br />stability under normal operating conditions. Colowyo goes on to say that it had <br />removed references to pond stability as a reason for necessitating manual pond <br />dewatering, leaving restoring capacity as a valid reason. We understand that <br />Colowyo wished to leave "restoring capacity" because of Colowyo's desire to have a <br />permit that would address manual dewatering of ponds until they are converted to <br />automatic dewatering.. If, however, the new individual permit will be issued <br />considering only automatic dewatering scenarios, we suggest removing "restoring <br />capacity" from the individual permit, as automatic dewatered ponds automatically <br />restore capacity. <br />WQCD did not elect to respond to this comment. We believe, however, that no <br />further comment from WQCD to DMG is necessary. The issue regarding pit pumped <br />water being classified as process water is between Colowyo and WQCD. <br />We do have a concern with our ability to discern washwater or pit pumped water <br />from surface runoff in a pond when conducting field inspections. If a pond were to <br />be filled to one-fourth of its capacity with wash water or pit pumped water, and a <br />