Problem 4.8. Determine the flood volume in ha-m (ac-ft) for a 50-year return period storm for the dormant season at your present location. The 360-ha (900-ac) watershed in row crops, terraced on Hydrologic Soil Group C in good condition for one-third of the area, and the remaining two- thirds is in woodland on Hydrologic Soil Group D in poor condition. Assume 25 mm (1 in.) of rainfall occurred 3 days prior to the design storm and the critical storm duration is 24 h.

Problem 4.8. Determine the flood volume in ha-m (ac-ft) for a 50-year return period storm for the dormant season at your present location. The 360-ha (900-ac) watershed in row crops, terraced on Hydrologic Soil Group C in good condition for one-third of the area, and the remaining two- thirds is in woodland on Hydrologic Soil Group D in poor condition. Assume 25 mm (1 in.) of rainfall occurred 3 days prior to the design storm and the critical storm duration is 24 h.

Structural Analysis

6th Edition

ISBN:9781337630931

Author:KASSIMALI, Aslam.

Publisher:KASSIMALI, Aslam.

Chapter2: Loads On Structures

Section: Chapter Questions

Problem 1P

See similar textbooks

Similar questions

Q2) A watershed has the following land use: a- 300 ha of open forest land b- 500 ha of good pasture land c- 200 ha of poor bunded cultivated land The soil is of hydrologic soil group A of 30% and 70% of group C. Estimate the runoff volume for the watershed under an antecedent moisture category III when two days of consecutive rainfall of 0.5 m and 0.7 m occur.
A 1000 acre reservior recieves 100 in of rain during a rainfall of 24 months. during this period, the mean flow to the stream is 10cfs mean outflow from the stream of 8cfs and an increase in storage is 4000 acre-feet. compute evapotranspiration in acre feet as well as inches
(a) Compute the runoff from a 2000 ha watershed due to 15 cm rainfall in a day. The watershed has 35% group B soil, 40% group C soil and 25% group D soil. The land use is 80% residential that is 65% impervious and 20% paved roads. Assume AMC II conditions. (7) (b) If the land were pasture land in poor condition prior to the development, what would have been the runoff volume under the same rainfall? What is the percentage increase in runoff volume due to urbanization? [Note: Use standard SCS-CN equations.]
Problem 4.3. By rational method, determine the design peak runoff for a 50-year return period. The watershed consists of 50-ha (120-ac), one third in rotation meadow and the remainder on row crops on the contour. The hydrologic soil group is B and the time of concentration is 30 min. The watershed is at your present location.
A watershed (area = 5,000 km2) was subjected to a 3-hr rainfall.
3. A watershed has an area of 300 hectares. Due to a 10cm rainfall event over the watershed a stream flow is generated and at the outlet of the watershed it lasts for 10 hours. Assuming a runoff/rainfall ratio of 0.20 for this event, find the average stream flow rate at the outlet in this period of 10 hours.
Determine the area weighted curve number for a watershed with 60% Roads, hard-surface, and 20% Farmsteads and 20% Straight row small grain with poor hydrologic condition, with Corresponding soil groups of C, D, C, and AMC II. Calculate the effective rainfall P* in this Watershed during a 100 mm storm event.
Design a 4:1 trapezoidal shaped vegetated waterway for a field in Sangamon County, Illinois for the given condition. The highest rainfall occurs during growing season after several days of dry period (antecedent rainfall condition is I). Hydrologic soil group is B. The grass waterway is designed to carry peak runoff rate from a 100-ha watershed, which has row crops on terraced lands with poor hydrologic condition, maximum length of flow is 500 m, and average watershed slope is 3%. The soils are highly erodible, and the waterway slope is about 4.5%. The vegetation is usually mowed (retardance group D), but the waterway should have adequate capacity when the grass is tall (retardance group B). Design for both cases. Provide final dimensions of top width, depth, and bottom width of the waterway. If any data is missing, make reasonable assumptions. (1) Estimate the peak runoff rate by the SCS TR-55 method from information provided above. Make reasonable assumptions, if any. (2) Follow the…
A catchment is having total area of 60 hectares. The rainfall intensity relation with duration for this catchment is given by the relation I = 100/(t+20), where I is in cm/h and t is duration of rain in min. (a) Draw the graph of rainfall intensity relation with duration at 10 min interval? (b) What will be the storm water runoff from this catchment if the average imperviousness factor is 0.63, and time of concentration is 35 min? (c) If population density of the area is 350 persons per hectare and water consumption is 170 LPCD, what will be the design discharge for separate system and combined system?
A 10-acre pond is located within a 640-acre watershed. The pond is lined with compacted class so seepage is negligible. During a thirty day period, the rain was 2.5 in. The average streamflow into the pond was 0.45 ft3 /s and out of the pond was 0.1 ft3 /s. By the end of the 30 days, the water level in the pond had risen 1.9 inches. Determine the evaporation over the 30 days in inches of water.
Determine the peak runoff (Nearest whole number) from a 100-year storm for the watershed described below: Field 1: 192 acres, 2% slope, cultivated, sandy soil Field 2: 38 acres, 8% slope, pasture, tight clay soil Field 3: 40 acres, 11% slope, woodland, silt soil The drainage way is 4000 feet with a 0.1% slope.
A 6-hour rain of average intensity 2 cm/hour falls over the fern leaf type catchment as shown in Figurebelow. The time of concentration from the lines AA, BB, CC and DD are 1, 2, 3 and 4 hours,respectively, to the site 0 where the discharge measurements are made. The values of the runoffcoefficient C are 0.5, 0.6, and 0.7 for the 1st, 2nd and 3rd hours of rainfall respectively and attain aconstant value of 0.8 after 3 hours. Draw surface runoff hydrograph from the runoff collected from thecatchment and also calculate volume of direct Runoff.