Effect of the Three Gorges Dam on Total Suspended Sediments from MODIS and Landsat Satellite Data

Total suspended matter (TSM) concentration is an extremely important parameter for water quality definition. The aim of this work is the evaluation of the effect of the Three Gorges Dam on total suspended sediments using remote sensing data at different temporal and spatial resolutions. TSM is estimated for the middle Yangtze river, China, before and after the construction of the Three Gorges Dam. The retrieved values are correlated to ground daily discharge values, finding relations between the physical quantities and discharge. Then, the application of the obtained relations to the discharge dataset provides continuous daily estimations of TSM values, also covering the days for which satellite scenes were lacking. This daily dataset will allow us to estimate the annual volume of river solid sediments. According to this work, both low spatial resolution MODIS (Moderate Resolution Imaging Spectroradiometer) data and high-resolution. Landsat 5 and 7 are able to detect the changes in TSM distribution over space and time induced by the building of the Three Gorges Dam, with a variation of even 50 mg/L over summer season. The confrontation of solid discharge with daily estimated TSM values shows that the single band MODIS algorithm performs better for medium-low concentrations, while the dual-band algorithm for MODIS and the selected Landsat algorithm perform better with high concentrations.

Nitrate, Total Ammonia, and Total Suspended Sediments Modeling for the Mobile River Watershed

This paper presents details of a water quality model of the Mobile River watershed that estimates total suspended sediments at the outlet of the watershed. The model is capable of simulating Nitrate (NO3), Total Ammonia (TAM), and Total Suspended Sediments (TSS) for extended periods of time at a daily temporal resolution (1970-1995). The Hydrological Simulation Program Fortran is used for modeling the hydrological, nitrogenous constituents, and sediment processes. Based on the nutrient simulation and exploration of the effects of two management practices (filter strips and stream bank stabilization and fencing) on nutrient removal, the resulting sediment model is used to implement the most efficient nutrient management practice and explore its effects on TSS concentrations in the Mobile River. Results show that the implementation of the management practice “stream bank stabilization and fencing” to agricultural lands in sub-watersheds that had intense agricultural activities produced the highest reductions of NO3 concentration (up to 14.06%) and TAM concentrations (8.01%). Based on the nutrient simulation and identification of “stream bank stabilization and fencing” as the most efficient BMP for nutrient concentration reduction, the sediment model was used to explore its effects on TSS concentrations in the Mobile River. Implementing “stream bank stabilization and fencing” produced monthly median TSS concentration reductions ranging from 3.6% to 10.6% in the Mobile River.

Nitrate, Total Ammonia, and Total Suspended Sediments Modeling for the Mobile River Watershed

This paper presents details of a water quality model of the Mobile River watershed that estimates total suspended sediments at the outlet of the watershed. The model is capable of simulating Nitrate (NO3), Total Ammonia (TAM), and Total Suspended Sediments (TSS) for extended periods of time at a daily temporal resolution (1970-1995). The Hydrological Simulation Program Fortran is used for modeling the hydrological, nitrogenous constituents, and sediment processes. Based on the nutrient simulation and exploration of the effects of two management practices (filter strips and stream bank stabilization and fencing) on nutrient removal, the resulting sediment model is used to implement the most efficient nutrient management practice and explore its effects on TSS concentrations in the Mobile River. Results show that the implementation of the management practice “stream bank stabilization and fencing” to agricultural lands in sub-watersheds that had intense agricultural activities produced the highest reductions of NO3 concentration (up to 14.06%) and TAM concentrations (8.01%). Based on the nutrient simulation and identification of “stream bank stabilization and fencing” as the most efficient BMP for nutrient concentration reduction, the sediment model was used to explore its effects on TSS concentrations in the Mobile River. Implementing “stream bank stabilization and fencing” produced monthly median TSS concentration reductions ranging from 3.6% to 10.6% in the Mobile River.

LOCAL ALGORITHM FOR MONITORING TOTAL SUSPENDED SEDIMENTS IN MICRO-WATERSHEDS USIN DRONES AND REMOTE SENSING APPLICATIONS. CASE STUDY: TEUSACÁ RIVER, LA CALERA, COLOMBIA

An empirical relationship of Total Suspended Sediments (TSS) concentrations and reflectance values obtained with Drones’ aerial photos and processed using remote sensing tools was set up as the main objective of this research. A local mathematic algorithm for the micro-watershed of the Teusacá River at La Calera, Colombia, was developed based on the computing of four component of bands from consumed-grade cameras obtaining from each their corresponding reflectance values from procedures for correcting digital camera imagery and using statistical analysis for study the fit and RMSE of 25 regressions. The assessment was characterized by the comparison of reflectance values and 34 <i>in-situ</i> data measurements concentrations between 1.6 and 33 mg L^&minus;1 taken from the superficial layer of the river in two campaigns. A large data set of empirical and referenced algorithm from literature were used to evaluate the accuracy and precision of the relationship. For estimation of TSS, a higher accuracy was achieved using the Tassan’s algorithm with the BAND X/ BANDX ratio. The correlation coefficient with <i>R</i>² = <i>X</i> demonstrate the feasibility of use remote sensed data with consumed-grade cameras as an effective tool for a frequent monitoring and controlling of water quality parameters such as Total Suspended Solids of watersheds, these being the most vulnerable and less compliance with environmental regulations.

Akurasi Metode IDW dan Kriging untuk Interpolasi Sebaran Sedimen Tersuspensi di Maros, Sulawesi Selatan

Physical conditions of seawater in coastal area can be studied by sampling at several locations. To perform spatial analysis, the data should be interpolated to get the values between sample points. Several approaches for interpolation may result in different outcomes. The purpose of this research is to compare Inverse Distance Weighted (IDW) and Kriging methods. Their parameters are studied using the total suspended sediments in Maros area, South Sulawesi. The results show that the more accurate interpolation is obtained by using IDW method than using Kriging method.

Akurasi Metode IDW dan Kriging untuk Interpolasi Sebaran Sedimen Tersuspensi

Physical conditions of seawater in coastal area can be studied by sampling at several locations. To perform spatial analysis, the data should be interpolated to get the values between sample points. Several approaches for interpolation may result in different outcomes. The purpose of this research is to compare Inverse Distance Weighted (IDW) and Kriging methods. Their parameters are studied using the total suspended sediments in Maros area, South Sulawesi. The results show that the more accurate interpolation is obtained by using IDW method than using Kriging method.