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OUTLINE OF DRAINAGE DETENTION CALCULATIONS <br />SHAKEY'S PIZZA PARLOR <br />1. THE TOTAL DRAINAGE AREA AFFECTED BY DEVELOPMENT = 0.5 <br />ACRES. <br />2. ALL DRAINAGE ORIGINATES ON THE SITE. <br />3. THE SITE CURRENTLY DRAINS NORTHWARD BY MEANS OF CATCH <br />BASINS AND PIPING ON THE EAST SIDE OF THE PROPERTY, AND A DRAINAGE <br />RAVINE ON THE WEST SIDE OF THE PROPERTY, TO A COMMON POINT SOUTHWEST <br />OF THE INTERSECTION OF THE BOTHELL-EVERETT HIGHWAY AND 94th STREET SF.. <br />4. THE SITE IS PRESENTLY USED AS A PARKING LOT WITH <br />APPROXIMATELY 30% ASPHALT CONCRETE PAVEMENT AND THE REMAINDER <br />COMPACTED GROUND. <br />5. THE SITE IS DESIGNATED ON THE CITY OF EVERETT DRAINAGE PLAN <br />TO FALL WITHIN AREA C, REQUIRING A DESIGN PARAMETER FOR CALCULATING <br />THE QUANTITY OF RUNOFF BEFORE DEVELOPMENT TO BE A STORM OF <br />FREQUENCY ONE IN TEN YEARS, AND FOR CALCULATING THE QUANTITY OF <br />RUNOFF AFTER DEVELOPMENT TO BE A STORM OF FREQUENCY ONE IN TWENTY- <br />FIVE YEARS, SINCE THE BEFORE AND AFTER RUNOFF FACTORS IN THIS <br />INSTANCE ARE EQUAL, THE DETENTION REQUIREVENTS ONLY RELATE TO <br />REDUCING THE RATE OF RUNOFF FOR STORMS GREATER THAN ONE IN TEN <br />YEARS. <br />6. THE COLLECTION SYSTEM CONSISTS OF A CATCH BASIN AT <br />THE LOW POINT WITH PIPING DIRECTING RUNOFF TO AN EXISTING CATCH <br />BASIN TOWARD THE NORTHEAST. RUNOFF INTO THE DRAINAGE RAVINE TO THE <br />WEST WILL NOT BE AFFECTED BY DEVELOPMENT. <br />Page 1 of 2 <br />