Hydrological Systems in the Greater Virunga Landscape: Water Quality around Mikeno Sector

Monitoring of environmental parameters is one of the highest priorities in the evaluation of environmental status of water resources and in environmental protection policy. The main objectives are to understand and evaluate the water quantity and quality in order to provide water of appropriate quality to various water users. The water quantity was assessed by the measurement of runoff or discharge at specific river cross sections using floating method for surface water and bucket and stopwatch method for springs and boreholes. The quality of river water and spring was identified in terms of its physical, chemical, and biological parameters. The analyzed data were compared with standard values recommended by WHO. Macroinvertebrates were collected in the rivers using a plankton nets and 10 minutes of sampling. Identification was made at the laboratory of Malacology. Results revealed that the quality of water obtained from sampling points is generally good to use for different domestic purposes except the Idanta River and Rwembwe borehole, which need an appropriate treatment before use. All sampling points are located far from houses and latrines, which can contribute to fecal contamination. On the different sampling points, bathing and washing clothes were observed and could constitute the source of pollution of drinking water. In Idanta and Kamira Rivers animals used water for drinking while also people use this water for domestic and drinking. In the two sampling points high values of Escherichia coli were found. No pollutant-taxa tolerant were found in the two monitored rivers for macroinvertebrates. Since water quality and quantity remain a major challenge in rural areas, the government should provide safe water to the population around Mikeno sector after treatment using suitable techniques.

Towards a Volumetric Variation of Lake Kivu Gases by the Nyamulagira and Nyiragongo Volcanoes

After the volcanic eruption of January 17th, 2002, Goma Volcano Observatory (OVG) initiated carbon dioxide (CO2) monitoring in the fractures south of the Nyiragongo volcano and at the northern edge of Lake Kivu. During the period from March 17th, 2017 to June 10th, 2020, twice a week, a GA 5000 gasometer was used for CO2 in the fractures as well as in the mazukus, respectively, as part of a project funded by the Kingdom of the Netherlands through the Lake Kivu Monitoring Program (LKMP) in Rwanda. The level of volcanic activity was determined by the volume of gas emitted by the volcano and measured by a DOAS and the seismicity measured by a network of 15 seismometers managed by the OVG. The results show that the concentration of CO2 in the active fractures from recent Nyiragongo eruptions varies with volcanic activity and the occurrence of a large earthquake in the East African Rift;but in the mazukus there is almost no relationship between CO2 content and volcanic activity. The study also shows that the influence of carbon dioxide in mazukus on the carbon dioxide into the Lake Kivu waters remains a major research question. The purpose of this study is to establish the relationship between the existing Carbon Dioxide (mazukus) in the Northern watershed and that of the deep waters of Lake Kivu.

Water Quality in and around Lake Edward Basin of the Greater Virunga Landscape, D. R. Congo Side

A systematic study has been carried out to assess the water quality in and around Lake Edward basin in D.R. Congo Side. Fifty four water samples were collected and analyzed for physicochemical parameters, including: temperature, discharge, pH, electrical conductivity, transparency, dissolved oxygen, COD, BOD, Carbonate, Bicarbonate, alkalinity, total hardness, turbidity, calcium hardness, calcium, magnesium hardness, magnesium, total nitrogen, ammonium, nitrate, total phosphorus, soluble reactive phosphorus, chloride, sulphate and total suspended solids. For bacteriological parameters: fecal bacteria, enterococcus bacteria, vibrio and salmonella shigella bacteria were considered. For macroinvertebrates assemblages all taxa using standards methods for each parameter. A comparison of data from dry (June to August) and wet (September to May) season was done in and around Lake Eduard watershed. The analytical data of various physicochemical parameters indicates that water characteristics in the watershed were in the limit of WHO standards for drinking water and aquatic life. Bacteriological water quality of some ecosystems in the watershed revealed the infestation of water with bacteria which make the water unusable for drinking by the surrounding population near and within Lake Eduard watershed. Longtime period sampling in the watershed is needed to understand the variation and composition of water quality and aquatic macroinvertebrate environment of the watershed.