**3.4 Rainwater harvesting**

*Resources of Water*

**3.2 Groundwater, an important additional source in urban centers**

monitoring of available water resources in Senegal's cities.

**3.3 Monitoring of conditioned water**

The exploitation of groundwater through wells/boreholes is widespread but is generally not regulated or monitored in many parts of Africa. As in many cities in Africa, there is a growing demand for groundwater in Senegal's main cities, mainly fueled by boreholes. Senegal has groundwater resources of about 4 billion cubic meters renewable every year and all the drilling currently carried out that pump this resource mobilizes a maximum of 6% of this resource. Thus, in terms of water availability, Senegal is relatively well endowed, especially since this resource is captured at depths that vary around 100 m. Freshwater stored in underground aquifers can be used effectively to divert the consequences of climate change. The availability of groundwater resources and their replenishment rates are uncertain, posing a serious problem for their management and protection [28]. Therefore, in the future, improved regulation and monitoring of groundwater withdrawals, in addition to appropriate management, will be essential for effective and sustainable

For the abstraction of groundwater in Senegal, dewatering works can be grouped into five major systems in order of importance: boreholes and modern motorized wells; modern wells and wells equipped with wind turbines; modern wells and wells equipped with hand pumps; modern wells with manual or animal drainage; traditional wells with manual or animal drainage [29]. Over the past decades, Senegal has therefore made significant efforts on national resources and with the support of its development partners to meet people's drinking water needs from groundwater. However, it must be recognized that despite the large invest-

In the various cities of Senegal, a good number of inhabitants use bottled water in bottles and sachets. From tap water to the bottle, to the plastic bag, there is a ladder of confidence in the quality of the water to drink, while the older practices of water consumption paradoxically provoke an attachment territorial, while presenting a status apart, since they are detached from any commercial thought. This is why it can be said that modern conditioning practices such as bottling and bagging create a new image of drinking water. Calibrated or formatted through models of different capacity, it pays off, and access is through formal and informal commercial distribution networks. Bottled water is present almost everywhere, from the big supermarket sign to the small neighborhood retailer, to the petrol stations, while water in sachets is mostly sold in small shops, in the urban neighborhoods of Dakar

ments, the demand for drinking water is far from being fully covered.

(Medina, Rebeuss …) for example, but also beyond, the capital [30].

Sachet water conditioning in Senegal is mainly in the informal sector of the economy. Anyone who has access to tap water and owns a refrigerator can create a "small business." This is a common practice in working-class neighborhoods. For modest families, it provides extra income. This ranges from bagging water in fine and transparent plastics, without any indication of source or quality of water, to water bags subject to prefectoral authorization with indications of the origin and characteristics of contained water. It is the work of individual and family initiatives, and represents an activity that involves the respect of certain health standards. The conditioning of the water is more a practical necessity, that of providing the body with the occasional need for water, with a taste that is supposed to be better than that of tap water. In Senegal, its consumption reaches significant proportions. In the streets of Dakar, at any time, it is marketed in bottles and especially in small plastic bags, exchanged for parts of 25 or 50 F CFA. Numerous, by the way, are those who

**110**

There is a regional imbalance in the recovery and distribution of water, and therefore in water security. In addition, the uneven distribution and variability of rainfall in sub-Saharan Africa impacts the annual water availability of households. In addition, climate change is constantly increasing extreme events such as droughts and floods with disastrous consequences for people's lives. Sub-Saharan Africa has abundant rainfall, but it is not evenly distributed and highly seasonal. Senegal experiences droughts and floods every year. It receives rainfall ranging from 200 mm in the dry parts (Sahelian domain) to more than 1500 mm in the southern and southeastern parts of the country (southern Sudan) [2]. Senegal's renewable freshwater resources vary considerably with time and region and cannot adequately meet the growing demand in large cities. Water harvesting could be an additional means of alleviating the problems of drought, scarcity and depletion of water resources. Surface water is scarce and groundwater exploitation is often not profitable. As a result, sustainable rainwater harvesting systems can be a very important solution to the problem of water scarcity. However, the collection of rainwater for domestic use in cities is not sustainable due to the configuration of the building and the diversity of activities that pollute the environment. However, for this rainwater to be a solution to the permanent shortages of water currently observed, it should first be captured and then treated before use [11].
