Estrada Uribe, Melisa. 2008.

Melisa Estrada Uribe. 2008. Stream water quality modeling: assessing the effects of waste water discharge in Puerto Berrío, Colombia. Master Thesis Proposal presented by Melisa Estrada Matrikelnummer 1276680 to the Faculty of Civil Engineering, Geo- and Environmental Sciences, Universität Karlsruhe (TH) Resources Engineering Study Programme Universität Karlsruhe (TH), Germany. April 2008. First supervisor: Prof. Erhard Hoffmann, IWG/SWW, Second supervisor: Prof. Hermann Hahn, IWG/SWW

Introduction

River water quality modeling is a useful tool in the description and prediction of changes in the characteristics of a river system. It is commonly used for forecasting changes in the water quality parameters caused by the discharge of point or non point sources. The present document presents a project proposal for the modeling of a branch of the Magdalena River in Colombia in order to assess the effects on the stream water quality caused by the wastewater discharged by the city of Puerto Berrío. The idea of the project arose with the need for proposing a water pollution control strategy for the city, due to the changes in the river flow, that lead to a reduction in the flow available for the dilution of the discharged wastewater. Modeling the stream shall provide useful information for decision-making regarding the most adequate water pollution control strategy. The first part of the document focuses on the definition of goal and objectives of the project, followed by the description of the proposed methodology, including a brief introduction to the different tools to be used. Finally, a work plan and a timetable present the different activities to be carried out for the achievement of the project and their respective deadlines.

Thesis statement

The goal of the project will be the assessment of the effects on the water quality along a branch^[1] of the Magdalena River caused by several wastewater discharges of the city of Puerto Berrío, Colombia. The results obtained by modeling the arm water quality shall serve as a tool for water resources management and be useful in evaluating water pollution control strategies for the city of Puerto Berrío.

Objectives

General objective

Assessment of the effects on the water quality of a branch of the Magdalena River caused by wastewater discharge of the city of Puerto Berrío, Colombia.

Specific objectives

• Literature review
• Study of the assessment unit and the city wastewater management including collection of primary and secondary data
• Application, calibration and validation of a stream water quality model
• Comparison of different scenarios
• Analysis and discussion of results

Methodology

The project will be developed in two general phases, each one of them including several steps and the use of different tools. The first phase will be the data collection followed by the second phase consisting of the data processing and analysis for obtaining results.

Data collection

Literature review: background, legislation, river modeling case studies, QUAL2K model’s user’s manual, other related works.

Secondary data collection: existing data of water quality monitoring and wastewater characterization Aguas del Puerto, 2007, hydrological, meteorological, and geographical data.

Primary data collection: field survey, water sampling and analysis performed either on site or by a water analysis laboratory. For the collection of primary data, the handbook Sampling for Waste Load Allocation Applications Mills et al., 1986, can be used as a guide. It contains sampling guidelines for the model QUAL2E, which is just an older version of the QUAL2K, but still very similar to the latter.

Related institutions

• Fundación Neotrópicos (Ecological NGO)
• Aguas del Puerto S.A. E.S.P (City Public Utilities Supply Company)
• Cormagdalena (Autonomous Environmental Authority)
• Corantioquia (Autonomous Environmental Authority)
• IDEAM (Institute for Environmental, Meteorological and Hydrological Studies)
• Instituto Geográfico Agustín Codazzi (Geographic Institute)
• DANE (Statistics National Department)

Data processing

River and Stream Water Quality Model QUAL2K

The initially suggested method used for the project development is the EPA’s QUAL2K river and stream water quality model. This is a one-dimensional, steady state model, whose features are the simulation of dissolved oxygen and oxygen demand, nutrients, tracer, algal dynamics, bacteria, pH and alkalinity.

The main input data for running the model are (see also Annex B and C):

• Reach identification and river mile/kilometer data
• Computational elements flag field data
• Hydraulic data
• Biochemical oxygen demand and dissolved oxygen rate constants
• Initial conditions
• Incremental inflow
• Headwater sources
• Point source or withdrawal

Detailed information about the model is found in the QUAL2K User’s Manual and Documentation Chapra et al., 2007.

The possibility of using a two-dimensional, hydrodynamic model such as the CE-QUAL-W2 is not ruled out. Once the available information is known, an assessment of the most adequate model will be done.

Geographic Information Systems (GIS)

For the analysis of the assessment unit, i.e. the Magdalena river segment, Geographic Information Systems such as aerial photographs, maps and map digitisation will be considered. These tools can also be useful for the graphical display of results. [IPF, 2006]

Principal Component Analysis (PCA)

For the first calibration of the model, already existing data provided by Aguas del Puerto to Neotrópicos will be used, but there is also the need for calibration and validation with updated data. For the selection of the parameters to be analysed and updated, the Principal Component Analysis (PCA) method is suggested. PCA is a useful statistical technique used to reduce multidimensional data sets to lower dimensions for analysis [Smith, 2002]

Leopold matrix^[2]

The Leopold matrix is a qualitative environmental impact assessment method, used to identify the potential impacts of an activity [Larry W. Canter]. It consists of the evaluation of the type (adverse of beneficial), magnitude and importance of the impacts caused by the activity. For the present study, this method can be useful in the comparison of scenarios, e. g. comparison of present scenario with a) future scenario if no measures are undertaken and b) future scenario after implementation of a water pollution control strategy. The present and future scenarios can be obtained through the modeling process. [This ought to be changed to causal relationship analysis]

Implications of the research

By means of already existing and new data it is expected to realise the calibration and validation of the water quality model QUAL2K, establishing the current effects produced by the wastewater discharges of the city of Puerto Berrío into the branch of the Magdalena River serving as receiving water body. The calibrated and validated model shall be useful for the prediction of changes in the stream water quality under various seasonal and other future circumstances such as increase or reduction in the available dilution flow, or variation in the wastewater characteristics. The model can also be applied to determine the total maximum daily loads (TMDL) according to the water quality standards, becoming a base for defining water pollution control strategies, i.e. the model will be an important tool in decision making in the city and the region.

The project implicates time investment and has high data requirements, not only in the amount but also and specially in the reliability. For future applications or replications of the model, new data will be necessary, which means that there should be cooperation between the institutions responsible for water resources and wastewater management in Puerto Berrío and in the region.

References

• Aguas del Puerto S.A. E.S.P. Plan Maestro de Vertimientos y Saneamiento Básico 2006-2026. Puerto Berrío, 2003.
• Canter, Larry. Environmental Impact Assessment. McGraw Hill, New York, 1996.
• Chapra, S.C., Pelletier, G.J. and Tao, H. 2007. QUAL2K: A Modeling Framework for Simulating River and Stream Water Quality, Version 2.07: Documentation and Users Manual. Civil and Environmental Engineering Dept., Tufts University, Medford, MA.
• Deisler, Flávio. Entwicklung eines Modells zur Abschätzung des aus Einleitungen resultierenden Schadstoffhaushaltes in Fließgewässern. Institut für Siedlungswasserwirtschaft, Universität Karlsruhe. Karlsruhe, Dezember 2004.
• Fundación Neotrópicos, Boada Sáenz Ingenieros. EIA + PMA encauzamiento del río Magdalena tramo Puerto Berrío – Barrancabermeja Informe final / I. Medellín, 2007.
• Istitut für Photogrametrie und Fernerkundung. Script to the Lecture GIS and Remote Sensing. Universität Karlsruhe, Karlsruhe, 2006.
• Mills, William, Bowie, George. Grieb, Thomas, Johnson, Kay. Handbook Stream Sampling for Waste *Load Allocation Applications. U.S. Environmental Protection Agency, Washington, 1986. Available at: www.epa.gov/waterscience/models/library/streamsampling.pdf
• Rinaldi, S., Soncini-Sessa, R., Stehfest H., Tamura, H. Modeling and Control of River Quality, McGraw Hill Series in Water Resources and Environmental Engineering. Great Britain, 1979.
• Rounds, Stewart, Wood, Tamara, Lynch Dennis. Modeling Discharge, Temperature, and Water Quality in the Tualatin River, Oregon. Water United States Geological Survey Water-Supply Paper 2465-B. Reston, Virginia, 1999.
• Smith, Lindsay. A tutorial on Principal Components Analysis. 2002. Available at: www.cs.otago.ac.nz/cosc453/student_tutorials/principal_components.pdf

---

Notes

1. ^ . The arm or branch is formed by the emergence of an elongated island in front of the city.
2. ^ . See comment about Leopold matrix and complementary or alternative analysis in the discussion page

Annex A

Thesis Provisional Table of contents

1. Introduction
2. Background
   1. Wastewater and water resources management in Puerto Berrío
   2. Institutional Framework
   3. Legal Framework and water quality standards
3. Assessing effects of wastewater discharge in Puerto Berrío
   1. River and Stream Water Quality Model QUAL2K
   2. System Segmentation and location of Pollution Sources
   3. Model Data Requirements
      1. Headwater data
      2. Reach data
      3. Meteorological data
      4. Water column data
      5. Light and heat input
      6. Point and diffuse sources and withdrawals data
      7. Hydraulics, temperature and water quality data
      8. Diel data
   4. Model Calibration
   5. Model Validation
   6. Generation of Future Scenarios by means of QUAL2K
   7. Results
   8. Comparison of Scenarios by means of QUAL2K
   9. Comparison of Scenarios by means of Leopold Matrix Causal diagram analysis
4. Discussion
5. Conclusion
6. Acknowledgments
7. References

Annex B

Segmentation schemes (Chapra et al., 2007)

[ilustración]

River with no tributaries

[ilustración]

Further subdivision into a series of n equal-length elements

[ilustración]

Annex C

Data Requirements for QUAL2K (Chapra and Pellitier, 2004)