The Baseflow Detective looking to uncover the secrets of Tanzania’s rivers

Interview with Hezron Philipo, GroFutures by Sean Furey, Skat Foundation

Hezron Philipo has a BSc in Geology (University of Dar es Salaam, Tanzania), MSc in Water Resources and Environmental Management (University of Twente at  ITC, The Netherlands) and is currently doing his PhD research at Sokoine University of Agriculture in Tanzania as part of the UPGro GroFutures project.

I caught up with him at 41st WEDC Conference in Nakuru, Kenya, where he explained the research that he is doing and what new insights him and his colleagues are uncovering.

[SF] What research questions are you focusing on?

HP: We are working particularly in the Upper Great Ruaha Catchment in Rufiji Basin – Tanzania to improve understanding of surface-ground water interactions, specifically: Is the lowland groundwater replenished by the river flow, or is it helping sustain the river flow?

[SF] And how are you tackling that question?

[HP] We are fortunate to have some long term records, which we are looking at in three periods: pre-1976, 1977-1998, and after 1998. In this last period there has been more human development in the catchment so we can start to see what impact that had on water in the catchment. There was also a strong El Nino event in 1997/98 that impacted East Africa.

We also installed new river and borehole monitoring loggers, and sensors that measures soil moisture at different levels down through the ground.

[SF] What did you find?

[HP] The soil moisture results are interesting for improving our understanding of how aquifer recharge works; we were expecting more soil moisture at shallower depths but it was higher deeper down.

Looking at the river, there is more baseflow (dry weather flow) in the river in the Highlands, and in the lowlands there is lower rainfall and higher evapotranspiration. However, our analysis of the river baseflow does not show a clear signal as to whether the downstream river is losing or gaining water from the underlying aquifer. Hopefully the emerging data from the new high-frequency monitoring stations will give us clearer answers.

A challenge is that the spatial distribution of monitoring points is limited and there are gaps in the data. However, the new monitoring stations that we installed will taken over by the river basin water board so that there are better data sets for future research and management.

[SF] How can you research be used?

[HP]  Recent observed reductions in river flow have impacted downstream users of this ecosystem service, which includes the Great Ruaha National Park, the Mtera Dam and raised concerns over the sustainability of irrigation via diversion canals.  Better monitoring and understanding of where the water is coming from is essential to water allocations across the whole catchment.

[SF] What are you plans for after your PhD?

[HP] I’m employed as a Hydrogeologist in the Ministry of Water and Irrigation working with Pangani Basin Water Board. Currently, I’m heading a position of a Water Officer for Arusha Sub-office. I hope to get a promotion and advance my career.

[SF] What do you see as the priorities for better water management in Tanzania?

[HP] Groundwater professionals are rare in Tanzania and the Pangani is just one of nine river basins. It is poorly monitored and the role of Government should be to invest in monitoring, but there is a lack of experts to advise Ministers. However, politicians often don’t trust experts and say that they waste money. This makes the sector dependent on international funding. This could change if the water Minister was also a water professional. Having monitoring is needed because groundwater modeling is complex and there is little data available, as a result many trained hydrogeologists often go into surface hydrology instead.

[HP] Surface water resources are declining and 80% of it comes from groundwater so it is a precious resource that needs professional monitoring, modeling and management

photo credit: S Furey, July 2018