CIVE 321 - Assignment 1

CIV E 321 – Principles of Environmental Modeling and Risk Homework Assignment #1 Due Tue, Feb 03, 2023, at 11:59:59 PM 1 Instructions: You are allowed to use Excel Question 1 Siwa Lake in the western desert of Egypt (Figure 1) has been undergoing an unprecedented increase in water level from one year to the next. This increase has been causing losses to productive agricultural lands, and flooding to critical infrastructure and roads thus increasing the risk of loss of lives of residents (Figures 2 to 5). This increase has been attributed to the excess inflow from the drainage of the nearby agricultural lands and uncontrolled flows from nearby groundwater wells. The lake loses water through evaporation only. Due to the seasonal fluctuation of the water levels across months as determined by telemetry installed in the lake (Figure 6), the surface area of the lake changes from one month to the other (Table 1). It is required to estimate the total incoming flow to the lake to investigate measures to ration the inflow and prevent any potential flooding of the lake in the future. Note that the salinity of the water in the lake is extremely high – approximately 210 ppt (part per thousand) [ seawater salinity is 35 ppt]. This hypersaline water is known to evaporate at much lower rates than freshwater. A reduction factor of 0.72 can be used for hypersaline water. The available inputs are shown in Table 1. Table 2 has the readings of the water telemetry measurements shown in Figure 6. It is required to: 1. Estimate the monthly inflow rate in m 3 per month. 2. Plot the cumulative inflow in m3 with the cumulative evaporation in m 3 on the same figure. Figure 1. Siwa Lake and surrounding agricultural areas that drain to the lake.

CIV E 321 – Principles of Environmental Modeling and Risk Homework Assignment #1 Due Tue, Feb 03, 2023, at 11:59:59 PM 2 Figure 2. Submerged agricultural areas with hypersaline water (M. Ammar, 2021) Figure 3. Submerged agricultural areas with hypersaline water (M. Ammar, 2021)

CIV E 321 – Principles of Environmental Modeling and Risk Homework Assignment #1 Due Tue, Feb 03, 2023, at 11:59:59 PM 4 Figure 6. Recorded hourly water levels from telemetry for Siwa Lake. The blue line represents the daily averaged and smoothed water levels. Table 1. Input data Month Area (hectare) Daily freshwater evaporation rate (mm/day) Jan 2906 2.9 Feb 2978 4.0 Mar 3016 5.2 Apr 2958 6.7 May 2925 8.5 Jun 2903 8.8 Jul 2895 9.2 Aug 2886 9.0 Sep 2872 7.6 Oct 2833 5.8 Nov 2905 3.8 Dec 2944 3.0 Table 2. Water levels over the year 2020 Date Water level (telemetry reading) 01-01-20 -16.09 01-02-20 -15.92 01-03-20 -15.82 01-04-20 -15.79 01-05-20 -15.80 01-06-20 -15.92 01-07-20 -16.04 01-08-20 -16.12 01-09-20 -16.20 01-10-20 -16.26 01-11-20 -16.24 01-12-20 -16.12 01-01-21 -15.96 L

Q1. SampahonS AS: p.*-*-E-) AS = Roui + Rin - E · g I salinity trap so mm/dul -> ms/day Areax days in a month AS RM - E · = 4Ah ms month mmaracnectar one seA-A nec, Holume change: AxAH(hee.) x orome Thectare = 10000mZ - Sample Calculations; 3 AH = 0.17 January: volume change = Area > AH = 2906ha x 0.17m x 0000m2 A S = 4940200m3 Evaporation Rat E = 0.72 +2.9m x 2906Ax 000m2 x Eldays a m day E = 1880995.68 m3

CIV E 321 – Principles of Environmental Modeling and Risk Homework Assignment #1 Due Tue, Feb 03, 2023, at 11:59:59 PM 5 Question 2 A dam is to be constructed for water supply in a certain area. The rainfall data for this area is shown in the table below. The Studies showed that a storm with a depth of more than 55mm will result in damage to the dam. How often this will occur? Also, if the design criterion for the dam is that the probability of dam failure is 5%. What would be the depth of the design storm? Table 3. Annual maximum rainfall depth Year depth (mm) Year depth (mm) Year depth (mm) 2006 26.13 1986 59.45 1966 26.05 2005 33.69 1985 56.58 1965 57.11 2004 31.87 1984 30.81 1964 34.85 2003 41.05 1983 37.81 1963 48.76 2002 30.79 1982 30.59 1962 53.54 2001 47.00 1981 59.96 1961 43.58 2000 52.84 1980 29.20 1960 31.19 1999 32.09 1979 40.35 1959 55.12 1998 26.05 1978 29.89 1958 40.79 1997 45.41 1977 41.07 1957 50.63 1996 52.12 1976 44.48 1956 35.30 1995 34.65 1975 46.92 1955 31.79 1994 30.40 1974 33.56 1954 54.12 1993 26.72 1973 48.32 1953 29.48 1992 33.81 1972 52.70 1952 40.72 1991 26.44 1971 27.74 1951 54.40 1990 53.06 1970 33.11 1950 30.54 1989 48.64 1969 33.15 1949 44.94 1988 41.34 1968 54.38 1948 32.82 1987 50.20 1967 49.56 1947 29.71

LILAR InFTUPOLATION y = 0.882 + (55 - 55 ex. 40)(0.002 = 0.098) p(X>55): 0.085

SO, T = t = to years / How often ? looking at the table above the depth would be at Amon

Q3. mRanK 2. 18OK AT Normal ONRORICITY PUPER on the next PaGE 2.P(X> 150mm) = m = 1 = 0.36 x 100 - 17030% 3.7 = 7;50 = 1 = 9 = 0.0922 + 100% = 3.33% looking @ normal probability paper Tomme

1. · ↑ & =- & · & · - ! = I ↑ 3.33 ⑨ = - - - - - - - & ② & ⑤ = &0 Annual Precipitation (mm)

① 4.

CIV E 321 – Principles of Environmental Modeling and Risk Homework Assignment #1 Due Tue, Feb 03, 2023, at 11:59:59 PM 8 Question 5 Using the Type III dimensionless cumulative rainfall diagram (values provided in Table 6) of NRCS (Natural Resources Conservation Service) and the IDF curves of Orlando, Florida (Figure 7), compute the rainfall hyetograph and the cumulative rainfall diagram (cumulative mass curve) of a 24-hour, 100-year return period storm at 1-hour interval. Table 6. US DoA SCS Rainfall Distributions Hour t t /24 Type I Type IA Type II Type III 0 0 0 0 0 0 2.0 0.083 0.035 0.050 0.022 0.020 4.0 0.167 0.076 0.116 0.048 0.043 6.0 0.250 0.125 0.206 0.080 0.072 7.0 0.292 0.156 0.268 0.098 0.089 8.0 0.333 0.194 0.425 0.120 0.115 8.5 0.354 0.219 0.480 0.133 0.130 9.0 0.375 0.254 0.520 0.147 0.148 9.5 0.396 0.303 0.550 0.163 0.167 9.75 0.406 0.362 0.564 0.172 0.178 10.0 0.417 0.515 0.577 0.181 0.189 10.5 0.438 0.583 0.601 0.204 0.216 11.0 0.459 0.624 0.624 0.235 0.250 11.5 0.479 0.654 0.645 0.283 0.298 11.75 0.489 0.669 0.655 0.357 0.339 12.0 0.500 0.682 0.664 0.663 0.500 12.5 0.521 0.706 0.683 0.735 0.702 13.0 0.542 0.727 0.701 0.772 0.751 13.5 0.563 0.748 0.719 0.799 0.785 14.0 0.583 0.767 0.736 0.820 0.811 16.0 0.667 0.830 0.800 0.880 0.886 20.0 0.833 0.926 0.906 0.952 0.957 24.0 1.000 1.000 1.000 1.000 1.000 P t /P 24 24-hour storm Linear interpolar is in 4 ⑦ Between

① 5.