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After project development;a percentage of the-land sixrface will be irripermeably covered with- _. - s.- `structures;concrete;and-pavement: This will have an attenuating effect on-the downward.migration _of nitrate:moleculesfrorii most of the subject.property_land:that is,or:has'been in agricultural l p ^: _�p - .�-_ = = ces of nitrate; reduction These im ermeable surfaces will'be traded for potential point sour ' specifically lawns and landscaping ornestic irrigation recharge can account for 250'to 1,500` gallons of water/day/residence during:the spring and'summer months.'°Excessive lawn and_Iandscape _ _ nitrogen fertilization;in combinationith excessive watering can lead to nitrogen leaching and + = _ runoff to open areas and retention basins-TTherefore, nitrogen fertilizer must be carefully applied to ;. _ ' lawns, gardens and landscaping. Due to the ekisting nitrate problem in the underlying groundwater, - . slow release nitrogen fertilizers should be used for lawn and landscape fertilization:'This type of 9� Y ,fertilizer is becoming more popular=in the_consumer.market and si:fhould have along-term benefcial £ effect on iitrate.iin act to roundwater, especially eciall �n areas such as the VaI eco _ - p _g :Section. . _ p Y The.following calculations show the cumulative areal nitrate loading from wastewater for th entire . �- F s _ _-• pTk Valpico Section;taking info account nitrate-loading redudons-due to wastewater treatment-from _ both the Castello Estates and Lin-nc Estates projects -=� = _ . - - -_ - 1 Wastewater loading rate: Currently there are approximately 340 homesites " ithiri the Valpico = a. Section.`Castello Estates will add approximately 83-homesites and Linrie Estates will initially add - Y ' 77 homesites= 500. However, as a safety factor,-since there are 640 acres in one square mile;640- _ _ homesites;or one home per acre on average will be used in the calculations �i - } _ . 2 The assumed nitrogen concentration in the applied effluent= 65,mg NIL . - - L �- _- .3 Nitrogen Loading= LN— LwCE" _ _- L:. Where: LN =N loading in lbs/ac•day :L - wastewater-loading in al/ac•da 200 als/household/da x l house/ac - _ r w - g. . g Y- g y - E 150 gals/day ac- CN c - _ _ C = 65 mNitrogen/L 6 - . _ -� N g Nitrogen/L�-� _ 1 , Conversion tactor=8.34'lbs/(106 •mg/L) _ .. LN =N Ioading in lbs/ac day (200 gals/ac day)(65�:mg NIL)(8.34)(10-6) !_ - - - - E =-0.108 lbs/ac:day. x 640 ac x:_365`day/yr=25,327 los-N m the:Valpico Section per.year -� _- S The Castello Estates,and Linne Estates project will comprise approximately 3S%:[of the Valpico: Section.: It-is our tuiderstanding that.the_wastewater,effluent from the Package Treatment Plant-must, - not exceed-5 mg N/L'or 7_.7%of the nitrogen concentration of.65 mg-N/L-in typical septic..effluent. `.The total amount of N released under the Valpico Section at 25;3271bs N, will be_ reduced by 35%_ - 16;462 lbs.N, which translates to 25;327- 16;%2 =_8,865 lbs N.lost due to the wastewater treatmentof _ - the Castello and Li nne Estates.projects However,.7.7%(5 mg NIL) of the 16,462 lbs of N must be _ Y :added back into the mass balance =-1-268 lbs N+-16,462.lbs N _.17,730 lbs N. Therefore this is equal to an annual 30%theoretical reduction in nitrate-nitro gen loadin over the e T. _ z _ entire- �,_ g CO Section. re Valpi gt - �W _ CConsult' - - :h __ ng