Water use efficiency in agriculture is also being improved through replacing earthen irrigation channels with concrete linings to reduce losses and upgrading flood irrigation systems (e.g. levelling of fields, neutron probes for soil moisture measurement, and scheduling of irrigation to plant needs). Groundwater use for irrigation above recharge rates in some regions is also undermining the economic viability of farming in affected areas. However, information on the trends in pollution from irrigated land is patchy. This has been associated with both human alterations of the hydrological characteristics of watersheds and land-use policies that have encouraged urbanisation in areas at risk to flooding events, and also increasingly the trend toward greater climatic variability leading to higher financial costs both through loss of production and damage to farm infrastructure, and also costs for the wider economy in terms of damage to property and in some cases loss of life.