- 2 A City Discharges 126000 M3 D Of Primary Effluent Into A Stream Take The Minimum Flow Rate Of The Stream To Be 136 M 1 (168.23 KiB) Viewed 38 times
- 2 A City Discharges 126000 M3 D Of Primary Effluent Into A Stream Take The Minimum Flow Rate Of The Stream To Be 136 M 2 (101.69 KiB) Viewed 38 times
- 2 A City Discharges 126000 M3 D Of Primary Effluent Into A Stream Take The Minimum Flow Rate Of The Stream To Be 136 M 3 (76.16 KiB) Viewed 38 times
- 2 A City Discharges 126000 M3 D Of Primary Effluent Into A Stream Take The Minimum Flow Rate Of The Stream To Be 136 M 4 (83.37 KiB) Viewed 38 times
- 2 A City Discharges 126000 M3 D Of Primary Effluent Into A Stream Take The Minimum Flow Rate Of The Stream To Be 136 M 5 (193.18 KiB) Viewed 38 times
- 2 A City Discharges 126000 M3 D Of Primary Effluent Into A Stream Take The Minimum Flow Rate Of The Stream To Be 136 M 6 (95.09 KiB) Viewed 38 times
- 2 A City Discharges 126000 M3 D Of Primary Effluent Into A Stream Take The Minimum Flow Rate Of The Stream To Be 136 M 7 (77.99 KiB) Viewed 38 times
- 2 A City Discharges 126000 M3 D Of Primary Effluent Into A Stream Take The Minimum Flow Rate Of The Stream To Be 136 M 8 (91.29 KiB) Viewed 38 times
- 2 A City Discharges 126000 M3 D Of Primary Effluent Into A Stream Take The Minimum Flow Rate Of The Stream To Be 136 M 9 (94.1 KiB) Viewed 38 times
- 2 A City Discharges 126000 M3 D Of Primary Effluent Into A Stream Take The Minimum Flow Rate Of The Stream To Be 136 M 10 (98.16 KiB) Viewed 38 times
- 2 A City Discharges 126000 M3 D Of Primary Effluent Into A Stream Take The Minimum Flow Rate Of The Stream To Be 136 M 11 (80.38 KiB) Viewed 38 times
- 2 A City Discharges 126000 M3 D Of Primary Effluent Into A Stream Take The Minimum Flow Rate Of The Stream To Be 136 M 12 (81.79 KiB) Viewed 38 times
1. OPEN CHANNEL FLOW GEOMETRIC CROSS-SECTIONAL PROPERTIES Table 1-0: Geometric properties of four commonly used cross-sectional shapes. Shape Wetted Top Hydraulic Hydraulic mean Area (Click on figure perimeter width radius depth A to enlarge) P B R D (Dm) by by b+ 2y B у b + 2y (b + zyly (b + zyly (b + zyly b + 2y (1 + z2)112 b + 2zy -D b + 2y (1 + z 2)/2 b + 2zy zy у zy? 2y (1 + z2)12 2zy 2 (1 + z2)112 2 (0 - sin e) do? e do (0 - sin o) de (0 - sin e) do de sin (0/2) 8 2 40 8 sin (0/2) Hydraulic diameter 4A D = P
FLOW AREA A WETTED HYDRAULIC PERIMETER P RADIUS R SHAPE SECTION B & Trapezoidal 1 у Ka y(b+ y cota) 2y bt sin a y(b+ y cota) 2y b + sin a z b Triangular y2 cota 2y sin a cOS a 2 Q 몰 Rectangular у by b+2y by b+2y - Wide flat by b у -b>>y> aD (a-sin a) 1-sina) Circular 8 PRESSURE IN AN OPEN CHANNEL Static pressure: Pstatic = yz = pgz Pressure for open channel: p(z) = ydcos(0) p = yzcos?(0)
CONTINUITY EQUATION дQ ДА + = 0 дх at Q = V,A1 = V₂A₂ BERNOULLI EQUATION: 02 H = (z + ycos?(0) + a + = (z+yce 29 Coriolis and Boussinesq coefficients Channel Column 1 Column2 В Column3 Column 4 - Minimum Maximum Average Minimum Maximum Average Regular channels, flumes, spillwa 1.1 1.2 1.15 1.03 1.07 1.05 Natural streams and torrents 1.15 1.5 1.3 1.05 1.17 1.1 River under ice cover 1.2 2 1.5 1.07 1.33 1.17 River valley, over flooded 1.5 2 1.75 1.17 1.33 1.25 UNIFORM FLOW EQUATIONS Manning equation: 1 Q = - AR2/351/2 n = A. Strickler equation: n = 0.047d366 Chezy equation: v = CR1/251/2 = CVRS Froude Number: V Fr = gy
SHEAR STRESS IN OPEN CHANEL To = ydsin(a) = or To = y d S (S is the longitudinal slope) 20 000 4 3 Line representing relations of tractive forces: 1b/ft2 = 0.5 x diameter in in. kg/m2 = diameter in cm (approx.) 10 000 3808 7000 6000 5000 4000 3000 NK Recommended value for canals with high content of fine sediment in the water IIIIIIII Fortier and Scobey: recommended for canals in fine sand with water containing colloids 8:800 0.700 0.600 0.500 0.400 2000 NK 0.300 Critical tractive force (g/m²) 1000 900 800 700 600 500 400 U.S.B.R.: canals with 2.5% 0.200 colloids in water U.S.B.R.: canals with Schoklitsch: recommended 0.1% colloids in water for canals in sand ENK 0.100 Recommended value for canals 8:888 with low content of fine Nuernberg Kulturamt (NK) 0.070 sediment in the water 0.060 11111-0.050 NK Recommended value for canals in coarse 777 0.040 noncohesive material size 25% larger 11 H0.030 Recommended values for canals with clear water 0.020 Straub values of critical tractive force U.S.B.R.: canals with clear water 0.010 Critical tractive force (Ib/ft2) 300 200 III 100 70 60 50 40 8:888 30 Fortier and Scobey: recommended for canals in fine sand and clear watert 0.007 0.006 0.005 0.004 20 0.003 10 0.1 0.2 0.3 0.4 0.6 0.8 1.0 0.5 0.7 0.9 3 4 5 6 7 8 9 10 20 30 40 50 60 80 100 70 90 Mean diameter (mm) RABIDLY AND GRADUALLY VARIED FLOW EQUATIONS or E = (y+army = () + gA = Specific Energy: E = (y+ a) Specific Momentum: S = Ay+ Head loss: E1 - E2 = AE/L = S, -Sg Hydraulic Jump: Y2 = {[V1 + 8Fr;? - 1] Critical depth, velocity and Slope: For trapezoidal cross section: yc: 0 = 1- Q2TC gAC For rectangular cross section: Yc = Sc g Dmcn2 b2g Rc3 Yı , Vc = gA Bs gn2 P Sc= Bs R1/3 302 Vc = gyc
Reynolds number: pvD Re = u Darcy-Weisbach: Laminar 64 f= Re Re < 2000 . Smooth turbulent (Blasius and Karman-Nikuradse): 0.3164 2.0 logo(Rev Re< 1 x 105 – 0.8 Reff) - f= t = Re14 Fully turbulent (Colebrook-White) and fully rough k 2.51 DH = 2.0 logo k (21) + = -2.0 log10 +1.14 + 3.71DH Reff ROUGHNESS HEIGHT OF MATERIAL Material E (mm) Concrete, coarse 0.25 Concrete, new smooth 0.025 Drawn tubing 0.0025 Glass Plastic.Perspex 0.0025 Iron, cast 0.15 Sewers,old 3.0 Steel, mortar lined 0.1 Steel, rusted 0.5 Steel, structural or forged 0.025 Water mains, old 1.0 MANNING COEFFICIENT OF MATERIAL n 0.013 -0.017 0.012 -0.018 0.011 -0.020 0.020 -0.035 0.030-0.40 Material Lined Channels: Asphalt Brick Concrete Rubble or riprap Vegetal Excavated or dredged channels: Earth, Straight and uniform Earth, winding, fairly uniform Rock Unmaintained Natural Channels: (width <31 m) Fairly regular section Irregular section with pools 0.020 -0.030 0.025 -0.040 0.030 -0.045 0.050 -0.14 0.03 -0.07 0.04 -0.10
PYSICALS PROPERTIES OF WATER Physical Properties of Water (SI Units) Dynamic viscosity Kinematic viscosity Temperature °C Specific weight Density 7 P kNm kg/m Surface tension 0 Nm Vapor pressure P kNm? UX 1036 N-s/m2 V x 1066 m/s 0 5 10 15 20 25 30 40 50 60 70 80 90 100 9.805 9.807 9.804 9.798 9.789 9.777 9.764 9.730 9.689 9.642 9.589 9.530 9.466 9.399 999.8 1 000.0 999.7 999.1 998.2 997.0 995.7 992.2 988.0 983.2 977.8 971.8 965.3 958.4 1.781 1.518 1.307 1.139 1.002 0.890 0.798 0.653 0.547 0.466 0.404 0.354 0.315 0.282 1.785 1.519 1.306 1.139 1.003 0.893 0.800 0.658 0.553 0.474 0.413 0.364 0.326 0.294 0.0765 0.0749 0.0742 0.0735 0.0728 0.0720 0.0712 0.0696 0.0679 0.0662 0.064 4 0.0626 0.060 8 0.0589 0.61 0.87 1.23 1.70 2.34 3.17 4.24 7.38 12.33 19.92 31.16 47.34 70.10 101.33
2. HYDROLOGY RATIONAL FORMULA: Q = = CiA C = coefficient of runoff that represents the characteristics of the catchment Q = peak discharge in m3s-1 i = intensity in ms-1 A = drainage area in m2 = Or = LC (icp) 6 where Qp (7.2) 3.6 Qp = peak discharge (m²/s) C = coefficient of runoff (11c.p) = the mean intensity of precipitation (mm/h) for a duration equal a to t, and an exceedence probability P A = drainage area in km² Runoff coeffiecient: N ΣC, A, 1 C = A Time of concentration: where t = 0.01947 20.77 9-0.385 (7.4) to = time of concentration (minutes) L = maximum length of travel of water (m), and S= slope of the catchment = A H/L in which AH = difference in elevation between the most remote point on the catch- ment and the outlet. SCS triangular unit hydrograph: tp = = 0.6tc tr Тр + tp 2 2.08A lp Тр To = 2.6772 = =
Runoff coeffiecient Value of C 0.05-0.10 0.15-0.20 0.18-0.22 0.30-0.50 0.60-0.75 Types of area A. Urban area (P = 0.05 to 0.10) Lawns: Sandy-soil, flat, 2% Sandy soil, steep, 7% Heavy soil, average, 2.7% Residential areas: Single family areas Multi units, attached Industrial: Light Heavy Streets B. Agricultural Area Flat: Tight clay;cultivated woodland Sandy loam;cultivated woodland Hilly: Tight clay;cultivated woodland Sandy loam;cultivated woodland 0.50-0.80 0.60–0.90 0.70–0.95 0.50 0.40 0.20 0.10 0.70 0.60 0.40 0.30 3. WATER QUALITY DO initial – D05 BOD= P BOD+ = BOD_(1 – e-kxt) Lt = BODu e-k*t CODE = CODu(1 – e-kxt) Lt = CODu e e-kut = Temperature correction (for river/stream water at a temperature of T°C) = K7 = K20 (T-20) 0 = temperature coefficient, it has a value of 1.056 at temperature s 20°C, and1.047 for temperatures higher than 20 °C.
Simple mass balance: V1 X BOD. + V2 X BOD2 BODmix = V1 + V2 CODmix Vi X COD. + V2 X COD2 V1 + V2 Variation of saturation concentration of oxygen in water (mg/l) with temperature T (measured in degrees C) is given by: C = 14.65 -0.41022 T +0.00791 T² -0.00007774 T Streeter-Phelps Equation kex U. + D= Dee -kx -k x U U. e -e LKL Where • D-dissolved oxygen deficit (mg per litre) at a distance x (m) from the point of contamination • Do - dissolved oxygen deficit at x = 0 (mg/l) • ka is the re-aeration coefficient (per day) • U, is the river velocity (m per day) • Lo is the ultimate CBOD at x = 0 (mg/l) • Kl is the BOD decay rate constant (per day) Calculation of initial oxygen deficit, or concentration of pollutant, from a point source D. = DupQup+D.Q + Q C down Cup Qup + CQ Qup + QE up The travel time (te) to the critical deficit is given by 1 t = In k k (-0. (ky - k.) 1-D. k_L, 8. k-k, The critical distance is given by x = U.
Equations for the reaeration coefficient at 20°C. If river depth > 0.6m and stream velocity < 0.55m/s, use O'Connor-Dobbins correlation ka = 3.9 11.5 If river depth > 0.6m and stream velocity > 0.55m/s, Use Churchill-Elmore-Buckingham correlation 0.969 kg = 5.03 H1673 If river depth < 0.6m, use Owens-Edwards-Gibb correlation < kg = 5.34 0.67 H1.85 For the three equations:- U is the average river velocity (m per second) H is the average river depth (m) T (°C) 0 20 Basic Properties of Water Water p (kg m) ji (Pa s) V v (m5) 1000 1.788x10-3 1.788x10-6 998 1.003x10 1.005x10-6 988 0.548x10-3 0.555x100 958 0.283x10- 0.295x10-6 50 100
Dissolved Oxygen Saturation Concentrations, mgL Temperature Chloride concentration, mgL °C 0 5 000 10 000 15 000 20 000 25 000 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 14.621 14.216 13.829 13.460 13.107 12.770 12.447 12.139 11.843 11.559 11.288 11.027 10.777 10.537 10.306 10.084 9.870 9.665 9.467 9.276 9.092 13.728 13.356 13.000 12.660 12.335 12.024 11.727 11.442 11.169 10.907 10.656 10.415 10.183 9.961 9.747 9.541 9.344 9.153 8.969 8.792 8.621 12.888 12.545 12.218 11.906 11.607 11.320 11.046 10.783 10.531 10.290 10.058 9.835 9.621 9.416 9.218 9.027 8.844 8.667 8.497 8.333 8.174 12.097 11.783 11.483 11.195 10.920 10.656 10.404 10.162 9.930 9.707 9.493 9.287 9.089 8.899 8.716 8.540 8.370 8.207 8.049 7.896 7.749 11.355 11.066 10.790 10.526 10.273 10.031 9.799 9.576 9.362 9.156 8.959 8.769 8.586 8.411 8.242 8.079 7.922 7.770 7.624 7.483 7.346 10.657 10.392 10.319 9.897 9.664 9.441 9.228 9.023 8.826 8.636 8.454 8.279 8.111 7.949 7.792 7.642 7.496 7.356 7.221 7.090 6.964