The Republic of Guinea’s hydrography is rich and varied. There are over 1300 rivers [1] - [3] . Many of Africa’s rivers and tributaries have their sources in Guinea [1] . However, one of the country’s most important watercourses is the Djoliba River, which is a remarkably important source of water for the populations of the African countries it flows through, including the town of Kouroussa, whose population is estimated at 42,134 [4] . The Djoliba or Djaliba river, the name of the Niger river in its Guinean course, after crossing the northern slope of the Daro Massif as a torrent, heads towards the plains of Upper Guinea, crossing the towns of Faranah, the urban district of Kouroussa and some of its villages and sub-prefectures. On its way, it meets other tributaries of the River Niger, such as the Niandan at Babila (confluent in French), the river (Korossala in the Malinké language) in the urban district of Kouroussa, before arriving in the Republic of Mali [5] . Figure 1 shows the confluence (the place where this river flows into the Djoliba River in the urban commune of Kouroussa, called Köbila in the drawer language or confluence). It flows for 643 km and occupies a catchment area of 70,000 km² in the Republic of Guinea. It is navigable from Kouroussa in (Republic of Guinea) to Bamako in (Republic of Mali) when the water level is high. On the other left bank of the river is a vast plain of grassland, providing fodder for livestock ( Figure 2 ). The two banks are linked by the historic and first metal railway bridge of the colonial era, built in the 1900s by the Boyer and Brothers metal construction factory, now Ets Star (Republic of France), over the River Niger and the water levels of the periods: May 31 and August 16, 2024, with the presence of riparian vegetation and washing and leaching activities ( Figure 3 ) [6] . It flows for 643 km and occupies a catchment area of 70,000 km² in the Republic of Guinea. However, the influence of human activities along the river means that this water resource is now threatened, as are most water sources in the Republic of Guinea [7] . Deforested and deformed riverbanks resulting from brick-making and digging for precious metals are just some of the factors that can threaten aquatic life [8] [9] . It should be noted that the riparian vegetation along a watercourse is responsible for producing shade on the watercourse. The presence of riparian vegetation considerably reduces water temperature and, as an added benefit, increases the concentration of oxygen in the water, thus promoting the survival of species. It also provides food and shelter for aquatic fauna, structures the morphology of the watercourse, and stabilizes the banks by fixing the soil with its roots [10] . This vegetation, which plays such a vital role in the survival of a watercourse, is now threatened by human activities. The level of pollution of the Djoliba River is a fact that most of the population urban of Kouroussa no longer consume it. In view of this problem of supplying drinking water from the Djoliba River to the population of Kouroussa, the Company of Water of Guinea (SEG) recently completed work to install and equip two new industrial boreholes in addition to the existing networks, in order to improve the drinking water supply system in the town of Kouroussa, whose current drinking water supply rate is 45%.

Although insufficient, this has improved water production and supply from 900 m³/day to 2300 m³/day [11] [12] . Numerous studies have been reported on the pollution of water sources worldwide, as well as in the Republic of Guinea [12] - [16] . However, to our knowledge, the Djoliba River in Kouroussa has been little studied, because 40 years ago, the waters of this river were the only major source of water supply for the urban population of Kouroussa. However, to our knowledge, the Djoliba River in Kouroussa has been little studied, because 40 years ago, the waters of this river were the only major source of water supply for the urban population of Kouroussa. The aim of this work is to determine the main physico-chemical causes of deterioration in the environmental quality of this important river over the last ten years, in order to propose some traditional solutions for improving this watercourse, which is in the process of disappearing as a result of human aggression during this last 10 years.

In this study of the Djoliba River at Kouroussa, it was observed that the river’s yield had deteriorated considerably over the last ten years as a result of natural and anthropogenic influences on the river [14] .

A watercourse showing a good hydromorphological state contributes to improving the proper functioning of the ecosystem of aquatic environments while strengthening its capacities to adapt to climate change [18] . According to [19] and [18] , by citing some elements that enter into the proper functioning of a watercourse and a disturbed or undisturbed hydromorphology indicates that: a diversification of the morphology of the minor bed of watercourses brings a heterogeneity of habitats (alluvial banks, wetlands, riffles), supports biodiversity in the watercourse, thus promoting its capacities for biological, chemical or physical transformations of organic substances brought to it from the outside (self-purification), natural banks as well as a stratified riparian forest, a place of habitation of numerous animal and plant species, a longitudinal ecological continuity allowing sediments and all fish or migratory fish to move. The observation of the Djoliba River in Kouroussa showed us an arid river from May 31 to 1, 2024, and anarchic occupations all along the river by human activities which led to the destruction of the arms of the river causing deformations in certain places of the normal river bed which causes each year in the heavy rains season, the flooding of homes near the river. For example, on the site (brickyard), there is an overflow of the river bed caused by these brick manufacturers of 29.7 meters from the natural river bed and 10 meters from the homes and a slaughterhouse next door not shown. Silting with puddles, stopping the flow of the river, measurement between the bank and the water level in the river bed, as well as the width of the bed which is (10 m) in May 2024. The results of occupation of the bank of the Djoliba River from 2014-2024 are mentioned in ( Table 1 , Figure 6 and Figure 7 ). However, our second visit on Djoliba River site on 16 August 2024 showed us a river completely filled with water, as shown in ( Figure 3(b) ). This filling of the river is thought to be due to the long period of rainfall in Kouroussa in August, with an average rainfall of 335 millimeters [20] . So, the water evacuations of runoff towards the river and the reloading of groundwater at the time of these heavy rains, would be sources of supply of water and sand to the river following the degradation of the soil over time (erosion phenomenon) disfavoring the rooting of trees, shrubs, bushes (riparian forest) ( Figure 1 and Figure 5 ) maintenance factor banks [21] [22] . The absence of riparian forest can also cause the movement of a watercourse [21] . The quantity of sand in the river has been transported gradually over the years and has increased by 0.13%. Thus, a trailing hopper dredging technique, for example, can be considered for the survival of this river. The granulometry analysis of the soil on the bank of the Djoliba River in Kouroussa (Republic of Guinea) allowed us to determine the apparent density of these two sampling points (PE 5 brickyard and E5 bridge). The results showed that the soil has a sandy-silty texture with apparent densities of 1.32 and 1.00 g/cm³ respectively and pH = 4.48 and 4.84. However, the soil density which is a necessary element for plant growth, because it determines the penetration capacity of the roots and the soil structure, according to [23] a soil with a texture of about 50% pore space will have an apparent density of 1.33 g/cm³. This value is close to that found at the sampling point bridge E5 which is at 1.32 g/cm³, and a difference of 0.33 with the sampling point brickworks PE 5 ( Table 2 ). The results of chemical analysis of the samples showed the presence of certain oxides such as: P₂O₅ and K₂O with contents: (25.10; 18.20 and 90.22; 104.50 respectively ( Table 3 ). It should be noted that although these oxides diphosphorus pentoxide (P₂O₅) and potassium monoxide (K₂O) are essential nutritional components for plant growth, as they represent the phosphorus and potassium content of many fertilizers [24] [25] , but their excess presence in water and soil samples is an indication of pollution. The sources can be: erosion, leaching; pollution with agricultural fertilizer, urban effluents, artisanal miners of precious metals who directly discharge detergents or other toxic solutions into the water. The percentages of organic matter (OM); organic carbon is: 2.10%; 1.35%. Those of the PE5 brickyard sample are: 2.20%; 1.10%. The contents of assimilable nitrogen; total nitrogen; carbon nitrogen ratio; sum of bases; Cation Exchange Capacity of the Point E and PE5 brickyard samples are: 5.40 mg/kg; 0.11 mg/kg; 12.271 meq/100g; 1.20 meq/100g; 5.10 meq/100g and 5.50; 0.10 mg/kg; 12.201 meq/100g; 2.10 meq/100g; 6.78 respectively.

This work shows the impact of anthropogenic activities on the Djoliba River in the urban commune of Kouroussa in the Republic of Guinea over the last ten years (2014-2024). The studies were based on the degree of degradation, riverbank and pollution of the river water. The results show that intensive agriculture, small-scale mining and the uncontrolled construction of buildings have contributed to the considerable degradation of the river and the quality of its biodiversity. The results of the physico-chemical analysis of the soil on the bank showed that the soil pH is acidic. The soil texture is sandy-loamy. The current state of the Djoliba River is a cause for concern and requires restoration to ensure the sustainability of this essential hydric resource for a large part of West Africa, through which the river flows (period without rain). To deal with it, an extensive reforestation and restoration programme of head and along of the headwaters major rivers by plant species adapted to aquatic environments, which combats erosion, balances the hydrological system and stabilizes the soil thanks to its roots, sand dredging techniques, the palisade fence used by certain Sahelian, destruction habitats and banning human activities, use of synthetic fertilizers by farmers on the bank vegetation could be an alternative. However, other additional studies are recommended because this document can be used by the Ministry in charge of the environment of the Republic of Guinea and even other African countries crossed by this river.