Modelling and sensitivity analysis of varying roughness effect on dispersion coefficient: a laboratory study

Abstract

a b s t r a c tFrequent disposal of effluent in rivers or streams in vicinity where the inhabitants rely majorly on it for domestic and agricultural purposes is dangerous, and that makes it relevant for precise modelling of dispersion coefficient or dispersion number. This will reduce under-estimation and over-estimation of this parameter as well as reduce frequent pollution assessment which have proven not to be sustainable. However, obtaining a model that will include all required parameter is still in process. This study considered the effect of varying roughness-which is the true nature of streams and rivers and its effects on the estimation of dispersion coefficient. It revealed that when varying roughness is increased by 1-unit, there will be an increase in dispersion number by 0.693 (t-statistics = 4.278; p < 0.05. In addition, an increase in 1-unit in the dispersion number value will require a decrease of both DO (t -ratio = -7.802; p < 0.05) and velocity (t -ratio = -4.992; p < 0.05) by 0.316 and 0.687 respectively. Sensitivity analysis further showed that roughness (K), dissolved oxygen (DO) are pertinent variables to be considered when dispersion co-efficient is to be modelled and have been previously left out. Furthermore, the ECM model generated, with R 2 = 0.98, prob(Fstatistics) < 0.005 and Durbin-Watson t-statistics of 2.107 respectively shows statistical significance of the model. Hence, it is suggested that varying roughness or roughness and DO should be introduced in dispersion coefficient or dispersion number models to improve its accuracy.

Assessment of geospatial and hydrochemical interactions of groundwater quality, southwestern Nigeria

“…Based on the hierarchical CG, a composite geospatial map of the study area was produced. Some tap water gets contaminated at the source and also after treatment unknowing to the consumers due to negligence to identify possible contamination points before being supplied publicly or privately (Tenebe et al 2017 ). These points of contamination are mainly from indiscriminate discharge from anthropogenic, commercial, or industrial activities (Olusheyi 2017 ; Tenebe et al 2018 ).…”

Heavy metal contamination and risk assessment on ecological and public health in a tropical estuarine river

“…point source (city lives, agriculture, atmospheric precipitation, etc.) pollutants with a view that the dilution strength is sufficient (Tenebe et al, 2017). Nowadays heavy metal pollution is a main problem in many developing countries like Bangladesh (Islam et al, 2015c).…”

Assessment of Daily Intake of Arsenic and Associated Health Risks for Children

“…This river is surrounded by industries and it is well utilized by the inhabitants for domestic and recreational purposes. Due to the open nature of the river, it is mostly used as a carrier of unwanted substances with the believe that with dilution and dispersion, these inherent pollutants concentration may be reduced [19]. Therefore, in this paper, we examine the health risk linked with surface water daily consumption of As to children.…”