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Trend detection in water quality data using time series seasonal adjustment and statistical tests
Author(s) -
Awadallah A. G.,
Fahmy Hussam,
Karaman H.G.
Publication year - 2011
Publication title -
irrigation and drainage
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.421
H-Index - 38
eISSN - 1531-0361
pISSN - 1531-0353
DOI - 10.1002/ird.570
Subject(s) - environmental science , water quality , hydrology (agriculture) , salinity , water resource management , statistical analysis , land reclamation , time series , trend analysis , statistics , geography , engineering , mathematics , geology , oceanography , ecology , geotechnical engineering , archaeology , biology
Abstract Detection of temporal and spatial trends can be considered one of the primary objectives of environmental monitoring networks. The overall goal of this paper is to make full use of water quality data available on Nile Delta drains in order to support the decision makers in managing the pollution problem. A more specific objective is to investigate several techniques in a systematic methodology to analyse water quality aimed at identifying temporal trends. Both seasonal adjustment time series analysis and statistical trend detection tests are used and compared. This approach was applied on two main drains in the Eastern Nile Delta (Bahr Hadus and Bahr El Baqar drains). The total dissolved salts (TDS) series was analysed as it has a length of 20 years from 1984 to 2004. The long time series gives an opportunity to apply both time series analysis and the statistical tests on the data and to compare the results of the two techniques. Both statistical techniques utilized arrived at the same results in general. The analysis showed improved (lower) salinity levels in the Bahr Hadus Drain. Although the Bahr El Baqar Drain belongs hydrobiologically to the same region, it is subject to fluctuations in salinity levels along the drain mainstream except near the outfall of the drain where the salinity level increased due to the reclamation activities taking place south of the Sahl El Hussania area. On the other hand, operation of the wastewater treatment plants of Greater Cairo have influenced the overall water quality conditions of the Bahr El Baqar Drain. Copyright © 2010 John Wiley & Sons, Ltd.