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~) .~ H~Vinq lald out the bnsic fiqure~ and having defined terms, It is now 903s1ble to recommend an a~proprlate ~oal for Denver for the next ten years. T~e primary rea30n for con3er~~t~on ~~ri~q ~his perlOQ is not a need to ~void the overtaxing of facillties, Qut si~pll the elimination of wasteful habLts and avoiding unnecessary transmountain d1- versions. It would seeM safe to a5su~e that a -5~~ reduction from the 1967 - 76 annual average per person lS llkely to be the mini- mum goal that might be accepted - whether by the federal and state governments or ~y the public at large. Any lesser goal would oe insignificant and hardly worth the eifort. ~~at effect would a mini~al -5% pro- grar.l ha'.re during the next ten years? The savings for the ~'Iest Slo~e '..;ould be from 12,000 to 15,000 acre-feet of water pEr year and the need for development of new su~pl~es fo~ Denver ~ould oe deferred from the late 1980s into the 19903. It is interesting to note that a mini- mal -5~~ program ~..ould also defer any need for Foothills by at le~st ten years. This ~s because any conservat~on ?rograffi directed at summertime watering will have its most dramatic impact on ~eak day usage. The "moderate" 1977 progra~, for example, lowered annual uSClge l:;y -10% but 10\"'ered peak day per person usage by -33%. A "~inirnal" -5% pro- gram - half as str~ngent as 1977's - ~ould probably hold pea~: demands to approx.~~ately 452 gallons per gerson per day, a -17~ red~ction from the standard usage of 541 gallons when no restraintS are ~rn?osed. At proJected growth rates, the popula- tion in the Water Board's serv~ce area in 1980 will oe 958,400. Holding consurnpt~on on a peak day to 452 gal~ons per person, (90 gallons per person ~ore than used on the day of peak consumption In 1977,) ~ould mean maximum consu~ption for the en- tire system in 1989 of 433 m~llion gallons ~er day (433 mgj) ~hich is far below the 520 mgd "rate~" c~pacity of the ;resent treat~ent facillties.. Th~re is clearly a large margin for erro~. Even if a ~onser- vat ion ~r00r~m ?roduced no reducti0n in . , peak day consurnpt~on per p~rson from the 1967 - 76 experience, the present Eacllitie5 would still be adequate. (541 gallons per person multi~lied by the proJected population of 958,400 equals 518 mgd.l In 1988, w~th a projected populat~on of 1,120,600 in the Water Board's service area, water consumption of 452 gallons per person on a peak day would mean a max~murn day total consumption that year of 506 mgd. past experler.ce in 1973 shows that present facilities can handle that quantity. Also, if experience in the early 1980s shows that a conservation program deslgned to reduce annual consumptlon by _5% fails to reduce peak day per capita consumption by -17% to the estinated 452 gallons per person, then the conservat~on program can be refined by establishment of a "hot line" communication link with schools and parKS and highway de- partments and other public agencies Nhich use large volumes of water. The next ten years is a~ple time for experimentation. The -17% reduction in. peak day demand which ~s implied and recommended in ar.y m~ni- mal conservation program des~gned to hold annual consumption per person at -5~ be1o~ the 1967 - 76 experience is not nearly as drastic as it might seem. The unrestrained peaks from which the -17~ reduction is measured is fa~ above any normal summer day demand. Daily consumption on most summer days is seldom close to the ~eaks on those very hottest of days ~hen demand skyrockets far above nor~al due to all lawnowners water- ing their lawns simultaneously. For example, even though peak day usage per person averag- ed 541.gallons during the 1967 - 76 base period, the average daily consumption per person during the hottest. month of each of those years ,...as only 390 gallons, :"28'% below the peaK, and the entire three month summer average usage was only 341 gallons per per- son, -37~; ~elow the pear... Consequently, a program ~hich holds peak day usage per per- son to -l7~~ ~eloH the 1967 - 76 experience ~ill not requ~re any enor~ous suppression of regular su~mer watering. For the next t~n years the people ot Denver can take a ~~~lrnal wa~er conservation 3 OnP'Q'J l