ii) Drop of groundwater table and land subsidence
Groundwater levels are dropping at an average of 2-4 metres per year, since the slow-filling aquifers have not been able to keep up with the growing number of water users and subscribers. This drop has caused unprecedented land subsidence of an average of 2-30cm in different plains across the country and sinkhole formation. All of these factors are contributing to massive desertification.
To restore this tremendous loss in the renewable capacity of aquifers, a holistic demand management scheme should be implemented to lower consumption by 11-12BCM per year. Most of the overexploitation occurs in the central basins where less surface water is available. Given the sustainability of the ancient qanats system to extract groundwater, the potential importance of qanats in helping to solve Iran’s water security challenges is unquestionable. Qanats convey water underground, which reduces evaporation, and only depend on natural gravity, rather than external sources of energy, for water transmission.
iii) Pollution
Pesticides and fertilizers are subsidized by the government and are therefore used extensively in agriculture. Irrigation water washes these chemicals into groundwater aquifers and agricultural run-off. Agricultural wastewaters are thus highly contaminated with chemicals that regularly contain heavy metals. Moreover, traces of nitrates are found in many urban sewage systems as well as in industrial effluents. This pollution makes water reuse controversial, introducing as it does potential threats to the environment and human health.
iv) Reluctant community participation in addressing water problems
With the collapse of Iran’s traditional and more sustainable water management system, many local communities have lost the sense of ownership and responsibility towards conservation and management of water resources they once had. This is evidenced by the careless use of water by farmers and the low water-use efficiency in the agricultural sector. However, the situation in most of the large cities, including Tehran, Isfahan and Mashhad, is different. Here, the general awareness level is high and the public demonstrates a willingness to engage in improving water-use efficiency.
v) Unreliable water data
The first step in any successful water management plan is to have reliable and precise water data. In Iran, groundwater-related data (wells and springs) are collected every five years through field visits and data series analysis. The water levels in rivers are monitored on a daily basis and measured twice per month. However, the monitoring equipment (including installed gauges and counters) is not sufficient and data from other sources, such as satellite images, are as a result of sanctions not available as a means to compare and verify ground data. In this regard, the data provided by various government offices often differ significantly, which inhibits a united response to water resources by the concerned authorities.
vi) Rushed solutions
In pursuit of water security, the government is currently considering alternative solutions to the rising water demand. One of the alternatives that is often referred to by government authorities is inter-basin water transfer, whereby water is imported from river basins outside the country, e.g. Tajikistan, or desalinated seawater is transferred from the Persian Gulf or the Caspian Sea. Although these schemes may provide a temporary remedy, in the long term they will add to the social and environmental complications. At the same time, such rushed solutions do not address the inefficient use of water. By improving water-use efficiency, particularly in agriculture, the water saved can be largely used in place of the transferred water introduced by these solutions.