LEGEND
SOILS GROUP BOUNDARY
A SOILS GROUP DESIGNATION
RCFC a WCD
HYDROLOGY J'vlANUAL - -- - -0 FEET !5000
HYDROLOGIC SOILS GROUP MAP
FOR
RIVERSIDE-WEST
PLATE C-1.15
PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies
RUNOFF INDEX NUMBERS OF HYDROLOGIC SOIL-COVER COMPLEXES FOR PERVIOUS AREAS-AMC II Cover Type (3)
NATURAL COVERS -
Barren
(Rockland, eroded and graded land)
Chaparrel, Broadleaf
(Manzonita, ceanothus and scrub oak)
Chaparrel, Narrowleaf
(Chamise and redshank)
Grass, Annual or Perennial
Meadows or Cienegas
(Areas with seasonally high water table,
principal vegetation is sod fonning grass)
Open Brush
(Soft wood shrubs - buckwheat, sage, etc.)
Woodland
(Coniferous or broadleaf trees predominate.
Canopy density is at least 50 percent)
Woodland, Grass
(Coniferous or broadleaf trees with canopy
density from 20 to 50 percent)
URBAN COVERS -
Residential or Commercial Landscaping
(Lawn, shrubs, etc.)
Turf
(Irrigated and mowed grass)
AGRICULTURAL COVERS -
Fallow
(Land plowed but not tilled or seeded)
Quality of~-S~o~i~l-G~r_o~u~p-~
Cover (2) A B C D
Poor
Fair
Good
Poor
Fair
Poor
Fair
Good
Poor
Fair
Good
Poor
Fair
Good
Poor
Fair
Good
Poor
Fair
Good
Good
Poor
Fair
Good
78 86 91 93
53 70 80 85
40 63 75 81
31 57 71 78
71 82 88 91
55 72 81 86
67 78 86 89
50 69 79 84
38 61 74 80
63 77 85 88
51 70 80 84
30 58 72 78
62 76 84 88
46 66 77 83
41 63 75 81
45 66 77 83
36 60 73 79
28 55 70 77
57 7 3 82 86
44 65 77 82
33 58 72 79
32 56
58 74
44 65
33 58
69 75
83 87
77 82
72 79
76 85 90 92
RCFC a WCD
HYDROLOGY NJA NUAL
RUNOFF INDEX NUMBERS
FOR
PERVIOUS AREA
PLATE D-5.5 (I of 2)
PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies
RUNOFF INDEX NUMBERS OF HYDROLOGIC SOIL-COVER COMPLEXES FOR PERVIOUS AREAS-AMC II Cover Type (3)
AGRICULTURAL COVERS (cont. ) -
Legumes, Close Seeded
(Alfalfa, sweetclover, timothy, etc.)
Orchards, Deciduous
(Apples, apricots, pears, walnuts, etc.)
Orchards, Evergreen
(Citrus, avocados, etc.)
Pasture, Dryland
(Annual grasses)
Pasture, Irrigated
(Legumes and perennial grass)
Row Crops
Quality of Soil Group .,_ __ ...., __ ,...._ ......
Cover (2) A B C D
Poor
Good
Poor
Fair
Good
Poor
Fair
Good
Poor
Fair
Good
66 77 85 89
58 72 81 85
See Note 4
57 73 82 86
44 65 77 82
33 58 72 79
67 78 86 89
so 69 79 84
38 61 74 80
58 74 83 87
44 65 77 82
33 58 72 79
(Field crops - tomatoes, sugar beets, etc.)
Poor
Good
72 81 88 91
67 78 85 89
Small Grain
(Wheat, oats, barley, etc.)
Vineyard
Notes:
Poor
Good
65 76 84 88
63 75 83 87
See Note 4
I I I
1. All runoff index (RI) numbers are for Antecedent Moisture Condition (AMC) II.
2. Quality of cover definitions:
Poor-Heavily grazed or regularly burned areas. Less than 50 per cent of the ground surface is protected by plant cover or brush and tree canopy.
Fair-Moderate cover with 50 percent to 75 percent of the ground sur face protected.
Good-Heavy or dense cover with more than 75 percent of the ground surface protected.
3. See Plate C-2 for a detail~d description of cover types.
4. Use runoff index numbers based on ground cover type. See discussion under "Cover Type Descriptions" on Plate C-2.
5. Reference Bibliography item 17.
RCFC a WCD
HYDROLOGY NJA NUAL
RUNOFF INDEX NUMBERS
FOR
PERVIOUS AREA
PLATE 0-5.5 (2 of 2)
PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies
ACTUAL IMPERVIOUS COVER
Land Use (1)
Natural or Agriculture
Single Family Residential: (3)
40,000 s. F. (1 Acre) Lots
20,000 s. F. (~ Acre) Lots
7,200 - 10,000 S. F. Lots
Multiple Family Residential:
Condominiums
Apartments
Mobile Home Park
Commercial, Downtown
Business or Industrial
Notes:
Range-Percent
0 - 10
10 - 25
30 - 45
45 - 55
45 - 70
65 - 90
60 - 85
80 -100
Recommended Value
For Average
conditions-Percent(2
0 20
40 50
65 80
75 90
1. Land use should be based on ultimate development of the watershed.
Long range master plans for the County and incorporated cities should be reviewed to insure reasonable land use assumptions.
2. Recommended values are based on average conditions which may not apply to a particular study area. The percentage impervious may vary greatly even on comparable sized lots due to differences in dwelling size, improvements, etc. Landscape practices should also be considered as it is common in some areas to use ornamental grav els underlain by impervious plastic materials in place of lawns and shrubs. A field investigation of a study area should always be made, and a review of aerial photos, where available may assist in estimat ing the percentage of impervious cover in developed areas.
3. For typical horse ranch subdivisions increase impervious area 5 per cent over the values reconmended in the table above.
RCFC a WCD
HYDROLOGY NlANUAL
IMPERVIOUS COVER
FOR
DEVELOPED AREAS
PLATE 0-5.6
PR-2024-001656 (TM) Exhibit 8 - MND and Technical Studies