南阳市境内大小河流百余条,总长度1800km,其中流域面积在100km~2以上的河流有78条,流域面积在5000km~2的河流有唐河、白河和丹江。境内年降水量790～1100mm,多年平均水面蒸发量89.2～1244.2mm;地表径流量68.03亿m~3,过境水量24.69亿m~3,地下水可开采量7.55亿m~3,合计100.27亿m~3,扣除丹江、老灌河汇人丹江水库的18.01亿m~3和地表水与地下水的重复计算量,该市实际水资源 Nanyang City, the size of the river more than 100, with a total length of 1800km, of which the river basin area of ​​100km ~ 2 more than 78, the river basin area of ​​5000km ~ 2 Tanghe, Shirakawa and Danjiang. The annual precipitation is 790 ~ 1100mm, the annual mean water surface evaporation is 89.2 ~ 1244.2mm; the surface runoff is 6,803,000,000 m ~ 3, the transiting water volume is 2,469,000,000 m ~ 3, the groundwater recoverable volume is 755 million m ~ 3, 3. Deducting 1.201 billion m3 of Danjiang Reservoir of Danjiang and Laogaihe people and repeated calculation of surface water and groundwater, the city’s actual water resources