Laserfiche WebLink
<br />MEMORANDUM <br /> <br />EOl EMMONS <br />& OLIVIER <br />RESOURCES <br /> <br />To: RCWD Technical Advisory Committee <br /> <br />From: <br /> <br />Carl Almer <br /> <br /> <br />Subject: <br /> <br />RCWD Rule Revisions <br /> <br />Date: <br /> <br />July 24, 2006 <br /> <br />The purpose of this memorandum is to provide an overview to the Technical Advisorv <br />Committee (TAC) of the rule revisions proposed by the Rice Creek Watershed District. <br /> <br />BACKGROUND <br /> <br />In the not too distant past, the goal of an urban drainage system was to rush water away as fast as <br />possible into a receiving stream or nearby lake or wetland. When it became evident that this was <br />not a sustainable water management practice, the approach changed to the routing of water into <br />detention ponds. Although many of these ponds were designed according to EPA's Nationwide <br />Urban Runoff Program (NURP) criteria based on 1980s studies, they too have some deficiencies <br />in effective treatment of runoff as can be attested by the quality of the District's lakes. <br /> <br />Figure 1. Quality of RCWD lakes <br />1~.0 <br /> <br />· \\11ite Bear Lake <br /> <br />Lake <br />Quality <br /> <br />Excellent Oligotrophic <br /> <br />....12.0 <br />" <br />~ <br />~ <br />~ <br />5.)0.0 <br />~ <br />,5 <br /> <br />. <br /> <br />Trophic Indices for <br />RCWD lakes (197H 998 <br />overoge). <br /> <br /><:: <br />~ <br />~ <br />:r. <br />:; 60 <br /> <br />~ <br />=- <br />~ ~.O <br />.:: <br /> <br /> <br />. <br /> <br />Good Mesotrophic <br /> <br />___ Valentine <br />.. <br /> <br />. .-" Peltier <br />. <br /> <br />- <br /> <br />2.0 <br /> <br />. <br /> <br />Baldwin <br />. <br />. <br /> <br />Poor <br /> <br />Eutro hie <br /> <br />Bad <br /> <br />, <br />; <br />1 <br />Hypereutrophic <br /> <br />. <br /> <br />. <br /> <br />0.0 <br />o <br /> <br />50 <br /> <br />100 <br /> <br />150 <br /> <br />200 250 <br /> <br />300 <br /> <br />350 <br /> <br />~o <br /> <br />TP (I.gn) <br /> <br />Today, we have learned that there are better ways to treat runoff water which is to let it soak into <br />the ground as close to its source as possible and mimic the natural hydrology of the system. This <br />not only limits the volume and rate of runoff that occurs, it also reduces the migration of <br /> <br />Emmons & Olivier Resources, Inc. <br /> <br />Page I of8 <br />