A watershed is 30% meadow (good condition) and 70% commercial and business areas (85% impervious). The watershed has 50% soil group C and 50% soil group D. Calculate the weighted Curve Number for the whole watershed. (CN for different land uses and Hydrologic Soil Groups are provided in the table below (Table 2-1 of the textbook)). Land Use Description Cultivated land¹ Without conservation treatment With conservation treatment Pasture or range land Poor condition Good condition Meadow Good condition Wood or forest land Thin stand, poor cover, no mulch Good cover2 Open spaces, lawns, parks, golf courses, cemeteries, etc. Good condition: grass cover on 75% or more of the area Fair condition: grass cover on 50%-75% of the area Commercial and business areas (85% impervious) Industrial districts (72% impervious) Residential³ Average lot size 1/8 ac or less 1/4 ac 1/3 ac 1/2 ac 1 ac Paved parking lots, roofs, driveways, etc.5 Streets and roads Paved with curbs and storm sewers Gravel Dirt Average % impervious4 65 38 30 25 20 Hydrologic Soil Group A B C D 72 81 88 62 71 78 68 39 30 45 25 39 49 77 61 54 51 69 79 84 89 92 94 95 81 88 91 93 98 79 86 89 61 74 80 58 71 66 77 55 76 57 72 81 85 57 088 8 85 82 61 74 80 83 70 77 68 98 98 90 91 81 83 78 86 70 80 85 84 98 98 98 79 *The remaining pervious areas (lawn) are considered to be in good pasture condition for these curve numbers. Sin some warmer climates of the country, a curve number of 95 may be used. 92 87 98 98 89 91 72 82 87 89 ¹For a more detailed description of agricultural land use curve numbers, refer to National Engineering Handbook, Section 4, "Hydrology," Chapter 9, Aug. 1972. 2Good cover is protected from grazing, and litter and brush cover soil. 3Curve numbers are computed assuming that the runoff from the house and driveway is directed toward the street with a minimum of roof water directed to lawns where additional infiltration could occur.
A watershed is 30% meadow (good condition) and 70% commercial and business areas (85% impervious). The watershed has 50% soil group C and 50% soil group D. Calculate the weighted Curve Number for the whole watershed. (CN for different land uses and Hydrologic Soil Groups are provided in the table below (Table 2-1 of the textbook)). Land Use Description Cultivated land¹ Without conservation treatment With conservation treatment Pasture or range land Poor condition Good condition Meadow Good condition Wood or forest land Thin stand, poor cover, no mulch Good cover2 Open spaces, lawns, parks, golf courses, cemeteries, etc. Good condition: grass cover on 75% or more of the area Fair condition: grass cover on 50%-75% of the area Commercial and business areas (85% impervious) Industrial districts (72% impervious) Residential³ Average lot size 1/8 ac or less 1/4 ac 1/3 ac 1/2 ac 1 ac Paved parking lots, roofs, driveways, etc.5 Streets and roads Paved with curbs and storm sewers Gravel Dirt Average % impervious4 65 38 30 25 20 Hydrologic Soil Group A B C D 72 81 88 62 71 78 68 39 30 45 25 39 49 77 61 54 51 69 79 84 89 92 94 95 81 88 91 93 98 79 86 89 61 74 80 58 71 66 77 55 76 57 72 81 85 57 088 8 85 82 61 74 80 83 70 77 68 98 98 90 91 81 83 78 86 70 80 85 84 98 98 98 79 *The remaining pervious areas (lawn) are considered to be in good pasture condition for these curve numbers. Sin some warmer climates of the country, a curve number of 95 may be used. 92 87 98 98 89 91 72 82 87 89 ¹For a more detailed description of agricultural land use curve numbers, refer to National Engineering Handbook, Section 4, "Hydrology," Chapter 9, Aug. 1972. 2Good cover is protected from grazing, and litter and brush cover soil. 3Curve numbers are computed assuming that the runoff from the house and driveway is directed toward the street with a minimum of roof water directed to lawns where additional infiltration could occur.
Chapter2: Loads On Structures
Section: Chapter Questions
Problem 1P
Related questions
Concept explainers
Reservoir and Streamflow Routing
In hydrology, a reservoir is usually a natural pond that is enlarged or made using a dam to keep the water clean. Reservoirs or dams can be constructed in several ways, including controlling the existing watercourse, disrupting the watercourse to form embayment within it, by digging or building any number of retaining walls.
Water Resource Systems Analysis
Water resources are natural water sources that may be as useful as water sources. 97% of the world's water is saltwater and only 3% is pure water; just over two-thirds of this ice sheet is located in glaciers. The remaining pure frozen water is found primarily as groundwater, with only a small fraction present above the ground or in the air. Natural sources of freshwater include surface water, under river flow, groundwater, and ice water. Artificial water sources can include treated wastewater (recycled water) and saline seawater.
Question
Transcribed Image Text:A watershed is 30% meadow (good condition)
and 70% commercial and business areas (85%
impervious). The watershed has 50% soil
group C and 50% soil group D. Calculate the
weighted Curve Number for the whole
watershed.
(CN for different land uses and Hydrologic
Soil Groups are provided in the table below
(Table 2-1 of the textbook)).
Land Use Description
Cultivated land¹
Without conservation treatment
With conservation treatment
Pasture or range land
Poor condition
Good condition
Meadow
Good condition
Wood or forest land
Thin stand, poor cover, no mulch
Good cover²
Open spaces, lawns, parks, golf courses, cemeteries, etc.
Good condition: grass cover on 75% or more
of the area
Eric
Fair condition: grass cover on 50%-75% of the
area
Commercial and business areas (85% impervious)
Industrial districts (72% impervious)
Residential³
Average lot size
1/8 ac or less
1/4 ac
1/3 ac
1/2 ac
1
1 ac
Paved parking lots, roofs, driveways, etc.5
Streets and roads
Paved with curbs and storm sewers
Gravel
Dirt
Average % impervious4
65
38
30
25
20
A
72
62
68
39
30
49
71 7 54598 8 76 77
77
61
45
25 55
57
Hydrologic Soil
Group
51
39 61
98
в с
81
72
71
89
81 88
79
58
66
89
61 74 80
78
69
92
88 6 7 刀0 4 份 4'
85
78
86
71
77
70
74
79
94
90
75 83
4The remaining pervious areas (lawn) are considered to be in good pasture condition for these curve numbers.
5In some warmer climates of the country, a curve number of 95 may be used.
91
72 81
70 80
68 79
98 98
98 98
D
85 89
91
81
83
77
80
84
98
91
82 87 89
95
93
92
87
86
85
84
98
¹For a more detailed description of agricultural land use curve numbers, refer to National Engineering Handbook, Section 4,
"Hydrology," Chapter 9, Aug. 1972.
2Good cover is protected from grazing, and litter and brush cover soil.
3Curve numbers are computed assuming that the runoff from the house and driveway is directed toward the street with a minimum of
roof water directed to lawns where additional infiltration could occur.
Expert Solution
This question has been solved!
Explore an expertly crafted, step-by-step solution for a thorough understanding of key concepts.
This is a popular solution!
Trending now
This is a popular solution!
Step by step
Solved in 3 steps with 2 images
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, civil-engineering and related others by exploring similar questions and additional content below.Recommended textbooks for you
Structural Analysis (10th Edition)
Civil Engineering
ISBN:
9780134610672
Author:
Russell C. Hibbeler
Publisher:
PEARSON
Principles of Foundation Engineering (MindTap Cou…
Civil Engineering
ISBN:
9781337705028
Author:
Braja M. Das, Nagaratnam Sivakugan
Publisher:
Cengage Learning
Structural Analysis (10th Edition)
Civil Engineering
ISBN:
9780134610672
Author:
Russell C. Hibbeler
Publisher:
PEARSON
Principles of Foundation Engineering (MindTap Cou…
Civil Engineering
ISBN:
9781337705028
Author:
Braja M. Das, Nagaratnam Sivakugan
Publisher:
Cengage Learning
Fundamentals of Structural Analysis
Civil Engineering
ISBN:
9780073398006
Author:
Kenneth M. Leet Emeritus, Chia-Ming Uang, Joel Lanning
Publisher:
McGraw-Hill Education
Traffic and Highway Engineering
Civil Engineering
ISBN:
9781305156241
Author:
Garber, Nicholas J.
Publisher:
Cengage Learning