Quantitative assessment of surface runoff at arid region: a case study in the Middle of Nile Delta

Bulletin of the National Research Centre

Table 1 Curve number values extracted from published tables listed in NRCS-CN, 1986 (TR-55) handbook manual

Land-use	Treatment	Hydrologic condition	Curve number for hydrologic soil group
Land-use	Treatment	Hydrologic condition	HSG A	HSG B	HSG C	HSG D
Bare soil	–	-–	77	86	91	94
Fallow	Crop residue cover (CR)	Poor	76	85	90	93
		Good	74	83	88	90
Cropland	Straight row (SR)	Poor	72	81	88	91
		Good	67	78	85	89
Cropland	SR + CR	Poor	71	80	87	90
		Good	64	75	82	85
Cropland	Contoured (C)	Poor	70	79	84	88
		Good	65	75	82	86
Cropland	C+CR	Poor	69	78	83	87
		Good	64	74	81	85
Urban area	–	–	98	98	98	98
Water	–	–	100	100	100	100

Poor factors impair infiltration and tend to increase runoff, good factors encourage average and better than average infiltration and tend to decrease runoff