During the last five years, Riyadh showed a fast urban and residential growth as the number of citizens increased by five times during this period. This increase has accompanied an increase in the water consumption to about 20 times. Unfortunately, this increase is bigger than what can be processed by the general facilities network, especially the sewage networks, which resulted in raising the level of underground water that caused critical economical and health issues, besides its effect on the bases of buildings, roads, sidewalks and the general facilities network. Given the seriousness of this problem, a program was launched by the high authority for Riyadh development to control the rising level in Riyadh and process its effects that included the formation of swamps which provided a suitable medium for the growth and spread of harmful insects that transfer diseases.
The program included a lot of studies which showed that the leaked water from the different sources exceeds the natural permeability of earth and rocks in Riyadh resulting in accumulation near the earth surface as well as the leaked water reaching the surface. Accordingly, a processing program was designed for this problem which consists of four main ways.
1. Control the sources causing the underground water level to rise
To eliminate water leakage from the main sources that cause the underground water level to rise. This program had a clear effect on reducing the leaked quantities.
2. The protective measures of public facilities protection
In order to make the protective measures to protect the public facilities, the current and future utilities the authority published a group of guide books “Towards a better place” which included the ways to execute the bases of, under the underground water level, irrigation systems design ways in the special gardens. It also included the considerations that should be taken for determining the spaces and sites of the gardens, in addition to cesspits design ways in a correct geometrical way. Finally, it either included the ways of designing and executing the plumbing inside the house with illustrations. The authority also published “Rules of designing and operating the underground water drainage and pumping systems, and designing and executing of the buildings bases and underground tanks to the water and the swimming pools”, in addition to “Rules of the establishment of buildings over the sensitive soil at the east of the city”. Furthermore, the authority published a lot of guidebooks and awareness bulletins on how to deal with it.
3. The continuous monitoring program
● watching the level and the quality of the underground water from about more than 260 monitoring wells
● monitoring surface water flow in Wadi Hanifa and Wadi El-sale
● monitoring the efficiency of programs aimed at reducing the underground water level periodically
● monitoring the resulting damages because of the underground water level rising.
All of the data are stored in the database to benefit from them when following up the underground water movement.
4. Reduce the level of underground water to safe levels
These levels are determined according to the circumstances of each district. The city is divided into three regions according to its geological composition as follows:
● The first region is located in the geological formation outcrop of El-Arab/El-Sale. This region was recommended to execute in a mutual drainage system for the torrent and underground water in it.
● The second region is located in El-Gbela formation. It was recommended to execute a sewage drainage system inside it to drain the underground water temporarily in the torrents and valleys so that this system can be used as a sewage system later.
● The third region is located in the east region of Riyadh, as the studies showed it is difficult to reduce the level of underground water to safe levels, because of the high sensitivity of the soils of these areas due to humidity changes.
More than 378 km of networks were executed to process the underground water level. A study about the possibility of executing programs about reducing underground water in the following quarters: El-Aared, El-Malka, El-Naseem Elgharby, El-Faysalya, Zahrt Laban, and Tuwaiq.
Projects and planning centers at the authority executed a study for the east Riyadh area and recommended:
● Putting a comprehensive program for monitoring by a 3-year executive period. The program has already begun at 20 Rabee El-Akhet 1436 AH.
● Develop a mathematical model for the underground water movement that studies the underground water movement expectations.
Also, an execution plan was developed to deal with the rising level of underground water in the east of Riyadh. This plan included:
● Apply building rules over the sensitive soil in the east of Riyadh
● Apply a project to reduce the underground water level in El-Naseem El Gharby quarter so that the level can decrease to about five meters from the surface.
● Continue developing a simulation model for the movement of underground water in the east of Riyadh
● Continue non-routine examinations that include installing devices to detect the earth movement, and water level in numerous monitoring wells
● Coordinating with the related development agencies
● Coordinating with the agencies responsible for the sources that provide the underground water.