Design and implementation of a citizen technician–based suspended sediment monitoring network: Lessons from the Tsitsa River catchment, South Africa

L.J Bannatyne,B.W Van Der Waal,K.M Rowntree,N Nyamela

doi:10.4314/wsa.v43i3.01

Abstract

Locally resident citizen technicians using basic equipment and Open Data Kit–enabled smartphones have collected flood-focused suspended sediment (SS) samples from 11 sites on the Tsitsa River and its tributaries, in the Eastern Cape Province of South Africa. In the highly degraded and gullied Tsitsa River catchment, existing modelled SS data were unverified and at odds with the results of studies based on dam sedimentation rates. Suspended sediment concentration (SSC), flux and yield data were required at subcatchment scale to support the prioritisation of community-based land rehabilitation initiatives in rural communal areas and to determine the relative contributions of subcatchments to SS yield at the site of the proposed Ntabelanga Dam. Approaches relying on researcher presence and/or installed instrumentation were precluded by cost, study area size, and the risk of equipment theft, vandalism and damage during high flows. Analysis of the quantitative data collected by the citizen technicians allows high-resolution SSC, flux, and yield data to be produced at subcatchment scale, which will be benchmarked by an acoustic SSC probe at a downstream Department of Water and Sanitation gauging weir. Qualitative descriptive and photographic data allows distant researchers to gain a real-time, catchment-wide overview of river and SS levels. This paper outlines the method, benefits and challenges of a direct-sampling approach that has the potential to address spatial and temporal challenges commonly experienced during SS sampling campaigns. Keywords: Tsitsa River, citizen science, flood sampling, suspended sediment, citizen technician, Open Data Kit, catchment restoration management

Highlights

In South Africa and globally, agencies involved with catchment management and monitoring require suspended sediment (SS) data to support their decision-making, planning, and interventions
This paper describes the design, implementation, benefits and challenges of the citizen technician–based SS sampling campaign that was undertaken in the Tsitsa River catchment, beginning in February 2015
Sites can be selected that fulfil well-established criteria likely to preclude recognised problems associated with monitoring, providing relatively stable platforms for consistent collection of accurate data

Summary

Introduction

In South Africa and globally, agencies involved with catchment management and monitoring require suspended sediment (SS) data to support their decision-making, planning, and interventions. The DWS gauging sites on the Mooi River at Maclear (T3H009) and on the Tsitsa River downstream of the study area at Xonkonxa (T3H006) were included within the monitoring programme design, whilst Solinst pressure transducers were installed at the remaining nine sites to generate continuous records of water stage (or level) for use in determining discharge.

Results

Conclusion