Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Accueil du site → Master → Pays Bas → 2001 → Spatial analysis of water quality and eutrophication controls in Lake Naivasha Kenya

International Institute for Aerospace Survey, Netherlands (2001)

Spatial analysis of water quality and eutrophication controls in Lake Naivasha Kenya

Mclean Patrick

Titre : Spatial analysis of water quality and eutrophication controls in Lake Naivasha Kenya

Auteur : Mclean Patrick

Etablissement de soutenance : International Institute for Aerospace Survey, Netherlands

Grade : Master of Science (MSc) 2001

Résumé
The design of a sampling scheme consists of defining the number, location and sample pattern of sampling sites. When temporal variations in the parameters being measured are relevant, the sampling scheme also must specify sampling frequency. Therefore in its most general form a sampling scheme determines where and how often to sample. Proper design of a sampling scheme will depend in part, on the objectives of the study. An objective common to many limnological surveys is the characterization of the water quality of an entire water body. However, it is frequently assumed that horizontal heterogenieties are insignificant relative to those occurring vertically. As a result, a single deep station is often established. In shallow lakes such as Naivasha which exhibit a high degree of patchiness, such an approach to sampling scheme design might not be appropriate. In this study spatial heterogenieties in a number of water quality variables in Lake Naivasha were examined to determine the optimal sampling locations and to estimate a necessary frequency and density of sampling for long term monitoring.The method used to determine optimal sampling locations is based on the theory of regionalized variables, and assumes that spatial dependence is expressed quantitatively in the form of the semi-variogram. It assumes also that the maximum standard error of a kriged estimate is a reasonable measure of the goodness of a sampling scheme.In second instance, the spatial water quality data were then used to evaluate the hydrochemical, nutrient and eutrophication status of the lake. Controls of the eutrophication process in Lake Naivasha were investigated using a dynamic water quality modelling approach.

Version intégrale

Page publiée le 11 janvier 2017, mise à jour le 13 novembre 2019