A DTS-based proof-of-concept framework for high-resolution sediment monitoring in water storage systems

ABSTRACT

Graphical abstract illustrating the DTS-based sediment monitoring framework, where diurnal temperature signals measured along a fibre-optic cable are analysed using analytical and numerical models to estimate sediment depth and support continuous reservoir sediment assessment.

Sedimentation in freshwater storages is an increasing concern under land-use change and climate variability. Conventional assessments often lack the spatiotemporal resolution needed for timely management. This study investigates distributed temperature sensing (DTS) as a method for estimating sediment depth based primarily on passive analysis of diurnal thermal signals, complemented by active heat-pulse testing to confirm the water–sediment interface (WSI). A fibre-optic cable (FOC) was deployed in a pond channel to record diurnal temperatures at two burial depths and the WSI over 2 days. The diurnal data exhibited systematic amplitude damping and phase lag with depth, consistent with diffusive heat conduction linking signal attenuation to burial depth. Analytical and numerical heat-transfer models were developed to relate signal attenuation to sediment depth and to predict thermal behaviour beyond instrumented depths. Modelled sediment depths agreed with independent measurements, with differences of approximately 10–14%. Results demonstrate that DTS can provide reliable, spatially distributed estimates of sedimentation, with accuracy influenced by the length of constant burial depth along the FOC and the strength of the diurnal signal. This DTS-based approach provides a transferable framework for continuous sediment monitoring with potential for scaling to larger systems, supporting targeted dredging, post-event assessment, and proactive management of reservoir storage capacity.1