Estimation of Peak Flood Discharge for an Ungauged River: A Case Study of the Kunur River, West Bengal

Table 4

Compute the weighted curve number (CN) using table value (see Table  5.5.2, p.150 in [33]).

Hydrological soil group	Major land use and soil characteristics	Covering basin area (%)	CN	Product
A	Urban area with 50 to 75 % impervious land	3	49	147
B	Moderate infiltration rate with coarse texture land, pasture, and open scrap area	7	79	553
C	Low infiltration rate with fine sandy loam, dense forest, and degraded wood land	55	77	4235
D	Fine clay to silt soil with agricultural land	35	72	2520
Thus, weighted CN = 7455/100 = 74.55		Σ100		Σ7455