Linking hydrology of traditional irrigation canals and socio-economic aspects of agricultural water use around Mt. Kilimanjaro

Jerome Kimaro1, Valeska Scharsich1, Bernd Huwe2, Christina Bogner3
1 Ecological Modelling and Soil Physics
2 Soil Physics
3 Ecological Modelling

P 2.3 in Understanding Ecosystem Services: Geoecological processes/functions with value for the society

Introduction

Efforts to improve the water supply within traditional irrigation furrows around Mt. Kilimanjaro were unsuccessful. We attribute this failure to a lack of information about the actual causes and extent of the problem. We suppose that there is a strong link between the socio-economic aspects like institutional and community management of the furrows and conflicts about water use. Therefore, we conducted a study to determine the relationship between current hydrological patterns and socioeconomic aspects of agricultural water use.

Material and Methods

We measured discharge at 11 locations along an altitudinal gradient on the southern slopes of Mt. Kilimanjaro. ASTER DEM image was downloaded from USGS website and GRASS GIS algorithm was used for terrain analysis. Additionally, we conducted focus group discussions with participants from 15 villages and key informants interviews (n = 15).

Results

We found that the mean discharge did not differ significantly between dry and rainy seasons (ANOVA, p = 0.17). The overall discharge pattern indicated that furrows located in lower altitude had higher mean monthly discharge rate of 14.37 L/s compared to 10 L/s at upper areas. Furthermore, 41% of furrows were seasonal, 22% dry and only 37% perennial. Findings from terrain analysis indicated a spatial variability of watershed morphological parameters such as size, drainage density, stream order and slope. Despite of a seemingly better water resource availability downstream, key informants and group discussions reported poor management of water on the district level that give less power to the local water management committees. Furthermore, encroachments in the Mt. Kilimanjaro National Park were reported. In particular, forest communities adjacent to the park are involved in illegal activities like logging, cultivation and cutting firewood. We attribute those encroachments to poverty, low environmental awareness and a lack of an effective forest patrol.

Conclusions

To resolve water use conflicts around Mt. Kilimanjaro, good governance practices including improved water distribution and resource management is required.