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Home My WebLink AboutPE 2.84.70; BROOKS WORTHINGTON; HYDROLOGY CALCULATIONS; 1984-11-28 (2)...... ...... YJ4 A. F- 5 C-o loo" POO kd 7- -7-1- :-W MVP 5 111-3 Qo Q~ tt SdJ A 1 /00 73A 37VOS UA CHA NNEL CHA R T VERTICAL b a 2 FT 13 Drainage Page 23 DRAINAGE DESIGN CRITERIA 1 GENERAL A.' All drainage design and requirements shall be-in accordance with the latest Master Drainage ' Plan and the requirements of the City Engineer and be based on full development of upstream areas. B. Public drainage facilities shall be designed to carry the ten-year storm underground, the 50-year storm to the top of curb and*the 100-year storm to the right-of-way lines. C*. The use of underground storm drain systems, in.addition to standard curb and'gutter., shall be required: When flooding or street overflow during 100-year.storm will cause serious damage. When.100-year storm flow from.future ups,tream ' development- Jas prop*osed in General Plan) will cause drainage problems. ~(3) when existing'adequate drainage facilities are-available' for use (adjacent to proposed development). (4) When more than one travel 1 ane of-arterial and collector streets would be obstructed by storm'water based on 10- orm- D. The.use of underground storm drain systems may be -required: (1) When the water level'in streets at the'q~~~ is within two inches of top of curb. When velocity of water in streets exceeds 11 FPS., When the water travels'more than 1,000 fleet overland. E. Permanent open drainage ditches will not be permitted in public right-of-way. F. 'The type of drainage facility shall be selected on the basis of ..' physical and cultural adaptability to the proposed land use. open channels may be considered in lieu of underground..systems when the peak flow exceeds the capacity of a 48-i.nch diameter RCP. Open channels shall-be fenced. G. Permanent drainage facilities* andright-of-way shall be pro- vided from development to point,of satisfactory disposal. H.. concentrated drainage shall not be discharged to City streets unless specifically approved by.the.City Engineer. 2. HYDROLOGY A. Off.site, use a blue-line print of the latest edition 200 scale San Diego County Topographic Survey Mapping. Show existing ~z Drainage Page 24 0 -culverts, cross-gutters.and drainage courses based on field Indicate'. the direction of flow; clearly delineate. review., each drainage basin showing.the area and.discharge and.the point of concentration. T B. '.Onsite,*use the grading plan. If grading -is-not to be done, then use a 100 scale' plan or great:er enlargement. Show all p roposed and existing'drainage facilities and drainage . . courses. Indicate the direction ,of flow.. Clearly delineate each drainage basin showing the area and discharge and the point of concentration.. C Use the charts in the Master Drainage Plah,for finding -the "Tc and D.- Use the existing or ultimate development, whichever gives thp highest "Coo factor. E. Use the rational formula Q=CIA for watersheds less.than 0.5 squaremile un ' 1&ss an alternate method -is a-pi)roved by-the City Engineer. For watersheds 'in excess of 0.5-square mile, the method of analysis shall be approved-by the City Engineer. prior to submitting calc-illations-. 3. HYDRAULICS A,' Street - Provide: Depth of-gutter-flow calculations. Inlet calculations. Show gutter flow-Q, inlet Q, and bypass Q on A plan,of the.street. B. Storm Drain Pipes and Open Channels Provide: (1) Hydraulic loss calculations for: Entrance, friction, junction, access holes, bends, angles, reduction and en- largement.- .(2) Analyze existing conditions upstream and downstream from proposed system, to be determined by the City Engineer-on a case-by-case basis. (3) Calculate critical depth and normal depth for open channel flow conditions. Show the HGL plotted on'a scale drawing of the pi pe or channel profile... '(5) Design for a non-silting velocity of -4~FPS in 'a two-year frequency storm unless otherwise-approved by the City, Engineer.. I Drainage— Page Z.) 4. INL ETS A Curb inlets at a sump condition should be designated for two CFS per lineal foot of opening,when headwater may rise to the top of curb... Curb inlets on a c ontinuous grade should be designed based on the following equation: Q = 0.7 L (a + y) 3/2 Where y = depth of flow in approach gut ter'in feet a = depth of depression of.FL at inlet in feet L = length of clear opening in feet Q '= flow in CFS Partial interception'shall be based on Bureau of Public Roads nomograph criteria. Grated inlets should be avoided w ' hen possible. When necessary, the design should be based on the Bureau of Public Roads Nomo- graphs (now known as the Federal Highway'Administration). D.. All catch basins shall have an access hole in the top unless access through the grate section satisfactory to the City Engineer is provided. Catch basins shall be located so as to eliminate whenever pos" sible concrete cross-gutters. Minimum connector pipe shall be 15". 5. STORM DRAINS Minimum pipe slope shall be .005 unless otherwise approved by the City Engineer.. Minimum storm drain size shall be.18" diameter. Provide cleanouts at 300 1 maximum spacing and at angle points and at breaks.in grade-greater than 10 0 .. For pipe*s 48".in diameter'. and larger, a maximum spacing of 500" may be used. The material for storiii drains shall.be reinforced concrete pipe, corrugated steel pipe, asbestos cement pipe, 6r .cast-in- place pipe designed-in conformance with San Diego County Flood Control District's design criteria, as modified by.Carlsbad Standard Specifications. Corrugated sr-eel pipe shall not be used in areas to be paved without the approval of the City Engineer. Any request to use corrugated steel pipe shall be accompanied by A report from.a qualified testing laboratory showing the Ph and minimum re- sistivity of the soils in which the pipe will be placed. The use of cast-in-place pipe shall be.subject to the specific approval.of the City Engineer., The pipe invert elevations, slope, pipe profile and hydraulic grade line shall be shown on the improvement plans. 09 00, ~101 t7,. Ff, o zo. '0 ~ , 44:~, rl Y'l w - i: ~ 6 op Tv -f L-T- t ---------- .. I 0 0', :"O~ - All- ,INEERS, INC. Street U 02008 r i ........ T-- - 7-1 77 '.42 oof _44 --- - ------- OF J6 ~77__