For the determination of the CN parameter, each methodological step used is outlined in Figure 2, including the hydrologic soil group
approach and the LULC data processing of the present and future scenarios, based on the City Master Plan of Caraguatatuba Municipality (Caraguatatuba City Council CCC 2011).
In Makhdoum's model the Hydrologic Soil Group
classification is presented as many important factors.
Soil curve numbers were selected assuming that pervious land cover for a given residence was a "lawn in good condition" (USDA 1996), and the hydrologic soil group
designations were "D" for Eden and "B" for the Switzerland and fine-silty family soils.
The hydrologic soil group
for the area under meadow is B and that for the row crop is C.
For each polygon associated with the 1: 24,000-scale soil survey maps, the following attributes were recorded: permeability, depth to high water table, hydrologic soil group
, and depth to bedrock.
The curve number is a function of land use and Hydrologic Soil Group
Source factors are soil test P, P application rate, nutrient application method, and grazing animals, whereas transport factors are underground outlets, erosion rate, hydrologic soil group
, field slope, P application distance to water, and filter strip width.
The boundary can then be used to clip the soils layer so that average slope and hydrologic soil group
can be determined.
Site soils were represented using the hydrologic soil group
(indicator of soil runoff potential) as defined by the U.
Soil types on subwatershed 526 consist of silt loam (74%, hydrologic soil group
B), fine sandy loam (17%, B and C), and loamy (9%, B) soils.
The values of the K-factor, hydrologic soil group
, and texture were then added as attributes to the polygonattribute table of the soil coverage for each map unit identification symbol.
Because of this, the Scotland District area is classified as Hydrologic Soil Group
(HSG) "D," according to infiltration criteria.