WPC  2B ZR0#|HP LaserJet 4HPLAS4.PRS 42xCQ\ZiXArial ItalicArial Bold ItalicArialArial Bold2X"m^CCUՠ5PP]CPCCCCCxȭ㠠CCCq5xC55x5ȅPxCxxxxP>PPCPP(PPP4PPPPPPuPCy_y_y_y_y_u[c[c[c[c[44444444}_y_y_y_y_y_y_y_y_l_y_yy_l_y_l_xxxxC+CCC5CCVxx555[I5PPPxpVxxCCC㭠xxlNx5PxCxxNTCPYXAAuuA.4PPPP酅uuuyxx5PuA"m^CPrխCPP]CPCCPP꭭Cȭ㠠PCPCPCCCՓ]Px]C]PCPP(PPP4PPPPPPuPChhhhhy_lclclclc<8<8<8<8lhhhhllllyhhhyhhyhC8CCCCCCpCCCcRC]]]}_PPP㻠xlVxC]PNTCP…YXIIuuI94xxPP酅uuuCxuIR y9NC,)+2xjAX z6NC, 2x, 1mC9,Xm2PXP /rC9,%=Xr2pPX"m^99Irr.EEPx9E99rrrrrrrrrr99xxxrщ~9gr~‰~999`r.rrgrr9rr..g.rrrrEg9rggggE5ExE9EE"EEE,EEEEEEdE~9oYoYoYoYoYηhQ]U]U]U]U40404040s]oYoYoYoYo]o]o]o]hYoYor~oYhYoYhYrrrggggrrrrrrrrrrrrr90999.99`ggr.r.r.UFr.rwrrrr•EEEgkQgg~9~9~9rrrrrr•g~g]J~grr.rEg~9ggrrrNH9nrE~rrrrrLKr??ddr?',EErEErrzzdddsgg.Ed?2 "m^9Earr9EEPx9E99rrrrrrrrrrEExxx~ɕ~9r~~‰~E9Exr9r~r~rE~~99r9~~~~PrE~rrrgP:PxE9EE"EEE,EEEEEEdE~9oYoYoYoYoYηhQ]U]U]U]U40404040s]oYoYoYoYo]o]o]o]hYoYo~~oYhYoYhYrrrrrrr~rrrr~~~~~~~~90999999`rr~9~9~9UF~9~w~~~~•PPPrkQrr~E~E~E~~~~~~ r~g]J~g~~9~Pr~Err~~~NH9rrE~rrrrrLKr??ddr?1,ggrEErrzzddds~~9gd? P  #Xp2PQXP# +  yxdddy Jicarilla Dulcex'`V(#5Conceptual Design   III. HYDROLOGIC DESIGN CRITERIA   R/ A.` ` Probable Maximum Flood  XX` ` The Probable Maximum Flood (PMF) is the maximum runoff condition resulting from the most severe combination of hydrologic and meteorologic conditions that are considered reasonably possible for the drainage basin study. The PMF for Dulce Lake was determined to have a maximum inflow of 77,652 cubic feet per second (cfs).(#`  R B.` ` Inflow Design Flood(#` XX` ` The Inflow Design Flood (IDF) for Dulce Lake Dam is equal to 60% of the PMF, 44,934 cfs. The existing spillway will pass about 1500 cfs before overtopping of the dam occurs, less than 3% of the PMF. A modification to the structure must be made in order to bring the dam into regulatory compliance.(#` XX` ` Presently, the difference between the emergency spillway and the top of the dam is approximately 6 to 7 feet. Replacing the existing spillway with 12 6' x 6' reinforced concrete boxes will allow the spillway to pass 3,984 cfs with no freeboard to the dam crest which is the 100 year flood. While this represents a significant improvement over the existing condition, this improvement will only pass a small percentage of the PMF. Consequently, armoring of the entire dam to protect against erosion from overtopping during larger flows appears to be the only feasible spillway alternative since there is no feasible way to enlarge or construct a new spillway. Increased flood detention storage would inundate the adjacent highway on the upper end of the lake. The probable depth and duration of overtopping for the IDF with the 12 6' x 6' reinforced concrete boxes',)) in place and the top of dam at elevation 7055 is 6.4 feet and 3 hours and 15 minutes, respectively.(#` XX` ` (#` ` ` The actual spillway design flow will depend on the ultimate spillway ` ` configuration chosen. The storage volume in the reservoir between the ` ` spillway crest and the maximum allowable water surface elevation will ` ` have a dampening effect on the inflow hydrograph. That is, some of the ` ` inflow volume will be detained in the reservoir, lowering the peak ` ` discharge and lengthening the time base of the hydrograph.  R C.` ` Development of Conceptual Improvements(#` XX` ` Topography (high sandstone bluff beyond the left abutment, the location of Highway 64 at the right abutment) and the magnitude of increased spillway capacity required preclude enlarging the existing spillway or locating and constructing auxiliary spillways. The only viable solution is a combination of a service spillway to pass smaller flood events and overtopping protection the entire length of dam to pass the inflow design flood.(#` XX` ` Two service spillway improvements were studied in the feasibility design report. They include 12 precast concrete boxes and a drop structure. The drop structure would pass the 50year flow before overtopping the crest, and would incorporate a low level gated pipe for irrigation and other releases. The 12 precast concrete boxes would pass the 100year flow without overtopping the dam. The drop structure as a service spillway was not pursued in this report because it is more expensive and passes a smaller flood. It is desirable to minimize the frequency of overtopping the armored embankment.(#` XX` ` The existing outlet works is not cost effectively repairable and will be(,)) removed. The new outlet pipe will be a 36 inch inside diameter pipe for ease of inspectability. The pipe will probably be precast concrete with a slide gate for low level releases to evacuate lake and control irrigation releases.(#` ` `