Assessment of the Impacts of Land Use Changes on Nonpoint Source Pollution Inputs Upstream of the Three Gorges Reservoir

Table 3

List of sensitive parameters calibrated and ranges and values of major parameters used.

Name	Description	Range		Optimum value	Sensitivity
		Min	Max
SDNCO^1	Denitrification threshold water content	0.908	0.987	0.974	0
PPERCO^2	Phosphorus percolation coefficient (10 m^3/Mg)	14.578	14.770	14.674	0.02
RSDCO^3rs	Coefficient for mineralization of the residue fresh organic nutrients	0.052	0.086	0.070	0.14
PHOSKD^4	Phosphorus soil partitioning coefficient	128.810	133.328	131.069	0.17
BC4^5	Local rate constant for organic phosphorus mineralization at 20°PHC (day^−1)	0.267	0.283	0.277	0.21
ERORGP^6	Phosphorus enrichment ratio	1.913	1.929	1.928	0.23
BC1^7	Rate constant for biological oxidation of ammonia nitrogen at 20°C (day^−1)	0.116	0.128	0.121	0.23
GWSOLP^8	Concentration of soluble phosphorus in groundwater contribution to streamflow from subbasin (ppm).	0.134	0.152	0.152	0.24
USLE_K^9	Soil erodibility factor (0.013 metric ton m^2 hr/(m^3-metric ton cm))	5.752	6.963	6.600	0.25
CMN^10	Rate coefficient for mineralization of the humus active organic nutrients	0.001	0.001	0.001	0.26
SHALLST^11	Initial depth of water in the shallow aquifer (mm H2O)	2.773	2.992	2.989	0.42
USLE_C^12	Minimum value for the cover and management factor	0.028	0.036	0.032	0.67
GW_DELAY^13	Delay time for aquifer recharge (days)	1.584	1.670	1.608	0.71
SPEXP^14	Exponent in sediment transport equation	1.270	1.270	1.270	0.81
ERORGN^15	Organic nitrogen enrichment ratio	1.926	1.930	0.154	0.9
REVAPMN^16	Threshold water level in shallow aquifer for revap or percolation to deep aquifer (mm H2O)	282.438	291.261	286.850	0.94
NPERCO^17	Nitrate percolation coefficient	0.583	0.609	0.596	0.95
CH_K^18	Effective hydraulic conductivity in main channel alluvium	54.074	55.028	54.551	0.98

 ^aSuperscripts of each parameter are their corresponding orders from the sensitivity analysis.