An assessment of sediment reuse for sediment management of Gallito Ciego Reservoir, Peru

Abstract

Gallito Ciego Reservoir, with a surface area of 14.2 km2 and mean depth of 40.3 m, is located in the Jequetepeque River basin in north‐western Peru. It is rapidly filling with sediments, endangering its main purpose of supplying agricultural irrigation water. A sediment volume corresponding to 70% of the dead water volume has accumulated in the reservoir up to 2007, with reservoir bottom outlet becoming blocked. Below the dam, 35 000 ha of irrigated cropland, supporting 115 000 habitants, are endangered. This study was conducted to evaluate the possibilities of sediment management, especially the use of the sediment for agricultural purposes in the Jequetepeque River basin. Sediment samples were collected from littoral and profound sites in the reservoir. Suspended sediments also were collected. Physical parameters were investigated, and the nutrient and heavy metal concentrations were determined. By comparing grain‐size distribution and nutrient content, as well as pollutant concentration of the sediments, to those of terrestrial soils near the reservoir, an assessment of the potential for applying the sediments on the cropland was undertaken. Texture investigations of profound sediments revealed a strong grain‐size classification within the reservoir. Because the heavy metal concentrations in the sediments were below toxic thresholds, and the concentrations of nutrients also were low, using the sediments for agricultural purposes would not constitute risks, although they cannot replace fertilizer. As a soil amendment and building material, the sediments do have an economical value. Its dredging and use, however, must be seen as only one component of more holistic sediment management of the Jequetepeque Watershed.

Aquatic ecosystem services of reservoirs in semi-arid areas: sustainability and reservoir management

“…Itaparica reservoir sediment has a low nutrient content, with a lack of nitrogen (0.8 g kg -1 P total , 2.8 g kg -1 N total and 28 g kg -1 C total ). However, the addition of silt and clay to soils increases the water storage capacity and ion exchange capacity, and improves soil quality parameters [30].…”

Testing decontaminated sediments as a substrate for ornamentals in field nursery plantations

“…Studies about their reuse in agriculture are still limited, and mostly relate to sediments that are dredged from reservoirs with contamination from agricultural waste and sewage (Fonseca et al, 1998;Canet et al, 2003;Walter et al, 2012). However, studies on sediments dredged from ports have demonstrated that decontamination techniques like phytoremediation and cocomposting can be successful for creating substrates for plant growth (Doni et al, 2013;Mattei et al, 2016Mattei et al, , 2017.…”

Re-oligotrophication of tropical water reservoirs to minimize environmental impact

“…Concerning re-oligotrophication, sediment abstraction will stabilize any thermal stratification, and by removal of organic rich sediments, the oxygen concentration of the overlying water will increase and the probability of redox chemical phosphorus mobilization will decrease. Up to the present only few a studies had been carried out to analyse the potential of this sediment management [31,32]. Sediment reuse is promoted by sediment sorting within reservoirs due to inflow current and wind wave action with resuspension of littoral sediments, coarse and fine sediments being deposited at different places.…”