Valuing groundwater recharge through agricultural production in the Hadejia-Nguru wetlands in northern Nigeria

This study applies a production function approach to value the groundwater recharge function of the Hadejia-Nguru wetlands in northern Nigeria. The gr oundwater recharge function supports dry season agricultural production whi ch is dependent on groundwater abstraction for irrigation. Using survey dat a this paper first carries out an economic valuation of agricultural produc tion, per hectare of irrigated land. We then value the recharge function as an environmental input into the dry season agricultural production and der ive appropriate welfare change measures. Welfare change is calculated using the estimated production functions and hypothetical changes in groundwater recharge and hence, groundwater levels. By focusing on agricultural produc tion dependent solely on groundwater resources from the shallow aquifer, th is study establishes that the groundwater recharge function of the wetlands is of significant importance for the floodplain. (C) 2000 Elsevier Science B,V. All rights reserved.