Fractal, predictability index and variability in trends analysis of river-water dynamics

ABSTRACT

Statistical modelling, analysis of physico-chemical parameters chemical oxygen demand (COD), biochemical oxygen demand (BOD), dissolved oxygen (DO), water temperature (WT), free ammonia (AMM), total Kjeldahl nitrogen (TKN), total coliform (TC), fecal coliform (FC) and potential of hydrogen (pH) monitored at the Hathnikund barrage (Haryana) sample site of river Yamuna in India have been studied. It has been observed that water-quality parameters such as COD-BOD, AMM-TKN, WT-pH and TC-FC are positively correlated whereas COD-DO, BOD-DO, TKN-FC and DO-WT are negatively correlated. For water-quality parameters such as pH, AMM, TC and FC no seasonal pattern is observed. Parameters such as COD, BOD, TKN, DO and WT follow a six-month seasonal pattern. All the parameters except DO and WT follow a positive trend for monthly and annual variations. BOD, AMM and TKN have anti-persistence behaviour for both monthly and yearly variations. For parameters COD (+27.83%), BOD (+42.36%), AMM (+49.63%), TKN (+22.71%), TC (+141.80%) and FC (+42.89%) the future trend remains positive with high variability. WT (−7.47%) follows a negative trend with low variation and DO (−17.12%) has a negative trend with lofty variation. Using fractal, predictability index and variability in trend analysis, it is concluded that all parameters, except pH and WT, cross the prescribed limits of WHO/EPA and if the same trend should be followed, then in the future the quality of water shall continuously deteriorate and water may not be fit for drinking, agriculture and industrial use.

Keywords:

• Regression analysis
• Hurst exponent
• fractal dimension analysis
• trend analysis

Acknowledgement

The first author is thankful to Sant Baba Bhag Singh Institute of Engineering and Technology for providing study leave to pursue a research degree.

Funding

The authors are thankful to the University Grant Commission (UGC), Government of India for financial support (F. 41-803/2012 (SR)); Central Pollution Control Board (CPCB), Government of India for providing the research data; Guru Gobind Singh Indraprastha University, Delhi (India) for providing research facilities.