cropland is becoming a larger source of water quality problems than point sources, according to CH Guadalquivir staff. Agricultural runoff tends to be high in nitrates, which affect water quality in reservoirs and promote eutrophication. Nitrates in drinking water supplies have been linked to a potentially life-threatening illness among newborns. Thus far, no systematic efforts to reduce nonpoint pollution such as that coming from runoff have been implemented in the basin.

# **_8.3 Incorporating Groundwater Management into the Surface Water System_**

Many problems have emerged in implementing the 1985 law’s integration of groundwater pumping into the water licensing system, and integration remains a work in progress.<sup>13</sup> In the Guadalquivir basin, approximately 20,000 wells out of about 100,000 total remain to be settled. Since 400,000 wells nationwide have been filed for but not yet settled, CH Guadalquivir’s backlog is not unique, and may even be comparatively small, but represents considerable unfinished business 20 years after the law was passed. In order for provisions of the 1999 amendments to work (especially the authorization of water transfers), CHs have to keep registries updated. The Ministry of the Environment has designated the completion and updating of registries as a priority and, if needed, will provide support for the information-technology tools to get the job done.

# **_8.4 Demand Management and Water Use Efficiency_**

Agricultural water use remains comparatively inefficient. The low efficiency of irrigation water use, and the lack of incentives for irrigators to do anything about it, are reflected in the fact that irrigators are still using canals built by Civil War prisoners in the 1930s. The water yield is 70% due to losses inherent in canal use and overall inefficiency. Drip irrigation systems cut these losses but involve high conversion costs and ongoing operational costs (and may reduce the amount of groundwater recharge resulting from the “return flow” of irrigation water applied on overlying land). The persistence of inefficient water use in the irrigation sector is due partly to pricing practices. Most irrigation users pay water tariffs based on their land surface rather than water use, so the tariff does not provide a financial incentive to conserve. Furthermore, the tariff irrigators do pay works out to roughly 1/20 of the amount paid by urban users in the Guadalquivir basin<sup>14</sup> —a significant subsidy of irrigators’ use of the water 13 The 1985 law itself contained an exemption that presents ongoing problems in integrating groundwater use into the basin management regime. Wells pumping less than 7,000 cubic meters per year only need to inform the CH of their existence, without having to obtain a license. On the other hand, the CH is required to verify that those wells are pumping less than 7,000 cubic meters per year, which is a time-consuming task requiring significant personnel resources. CH Guadalquivir estimates that there were 27,000 such wells in the basin when the law was adopted in 1985, and there are 40,000 such wells in the basin now.

14 Calculated as follows: water tariffs in irrigated areas within the basin range between 6 and 210 euros/ha, with the large variation reflecting different water sources and irrigation areas. The average price, including bulk water rates and irrigation community charges, is difficult to calculate but 120 euros/ha is a good approximation. If we take an average water allowance of 7,000 m<sup>3</sup> /ha, the average price per m<sup>3</sup> would work out to around 0.02 euro/m<sup>3</sup> , compared with an approximate average of 0.80 euro/m<sup>3</sup> paid by water users in municipal water systems in the basin. Since about half the cost paid by urban users is for sanitation 28