HYDROMETEOROLOGICAL STATIONS DISTRIBUTION AND PARAMETER TRENDS IN TIGRAY.

Abstract

The effective management of water resources in Ethiopia's topographically complex Tigray Region is critically dependent on a robust hydro-meteorological observation distribution. However, the existing distribution suffers from severe deficiencies in spatial coverage and operational integrity, creating significant uncertainty for water resource planning. This thesis provides a systematic evaluation of the hydro-meteorological distribution in Tigray, analyzes long-term trends in key climatic and hydrological parameters, and proposes a data-driven framework for its optimization. The study employed a mixed-methods design, integrating Geographic Information Systems (GIS) to assess spatial adequacy against World Meteorological Organization (WMO) standards, non-parametric statistical tests (Mann-Kendall, Sen’s Slope) to analyze long-term (1960–2024) data, and field verification to assess operational status. Results reveal a network in critical failure. The conventional station network meets only 51% of the WMO minimum requirement, with precipitation stations achieving just 17% of the necessary coverage. This spatial gap is compounded by an operational collapse, with only 13% of the required stations currently functional, creating vast unmonitored areas. The streamflow gauging network is similarly sub-optimal, while the modern Automatic Weather Station (AWS) network is nascent. Trend analysis identified no significant long-term change in regional rainfall or streamflow. In conclusion, the existing monitoring infrastructure is structurally imbalanced, spatially biased, and operationally crippled, rendering it unfits to support reliable water resource assessment or climate-resilient development. This thesis culminates in a strategic roadmap with prioritized recommendations for the phased expansion and modernization of the network to build a scientifically robust observational foundation for the region.