Hydrodynamic and Water

Quality Modeling in Lakes and

Reservoirs

By:

Behnam Zamani-Gharehchaman MSc. In Water Resources Engineering

PhD student in Civil and Environmental Engineering

Supervisor:

Prof. Dr. Manfred Koch

Contents

Introduction and Overview

to Hydrodynamics and water quality in Lakes and

Reservoirs

Modeling Hydrodynamics and water quality in Lakes and Reservoirs

Application Example

PhD research

2

Introduction To Hydrodynamics

and Water Quality

3

introduction

Freshwater

Rivers Lakes and Reservoirs

Salty Water

Coastal Ocean

Estuaries

Surface Water Numerical Modeling

4

introduction

Coastal ocean and Estuaries

The Population in these areas will be doubled by 2025

A half of World Population (3 Billion) live in the coastal areas and estuaries

will be doubled until 2025

Food, Life, Business, Industry everything depends on ocean and sea

5

introduction

Coastal ocean and Estuaries

Pollution Control Is one of the most critical environmental

concerns in the coastal areas

Water quality and Ecosystem are mainly affected by the release of

urban, industrial and agricultural waste

and waste-water

6

introduction

Surface freshwater resources include only 0.88% of the

whole usable water in the hydrosphere and beside the groundwater

supply the needs for freshwater.

Lakes and Reservoirs

Lakes and Reservoirs contain the 90% of reserved liquid surface freshwater.

7

Climate change (Global Warming)

Rainfall loss

Water retention time

Lakes and Reservoirs

Stratification and Eutrophication in the lakes and

reservoirs lead to the degradation of water quality and the disability of the aquatic environment to supply in-lake and downstream ecosystem.

introduction

Prediction of Water Quality in lakes and reservoirs is one of

the most critical issues in the lake and reservoir environment and

operations.

8

Water Resources Quality Management

Observation Theoretical

Analysis Numerical Modeling

Hydrodynamic and Water Quality models are now

unavoidable to use in water resources management and studies

Complexity of natural aquatic environments

Development in computational capabilities in temporal and

spatial simulation of aquatic ecosystems

Based on differential equations and numerical methods

introduction 9

introduction

Iran with many dam construction projects either built or under

construction, is one of the fast developing countries in dam projects

in the world.

The structural point of view in developing countries always

leads to pay less attention to water quality in reservoirs and the

interaction between the water and environment .

Many reservoirs in developing countries do not have a definite

and master plan for water quality management on withdrawn and

released water and in-lake environment.

10

Modeling Hydrodynamics and Water

Quality in Lakes and reservoirs

11

Water Quality Models

Steady state,

input-output models

Ecological models

Coupling Ecological model with

Hydrodynamic drivers

12

Hydrodynamic Models

Heat transfer . Stratification and

mixing . Scalar mixing and

transport . Wind energy and wind

induced momentum . Solution of

Free surface evolution and

velocity equation . Horizontal

diffusion of momentum and

scalars . Advection of scalars

13

Water Quality Models

Contaminants

Nutrients (N-P-C-Si)

Biochemical model

Air-Surface interactions

Algae.Fish.Bacteria.Zooplankton

Seagrass

Sediment-Water Interactions

Diagenesis

14

Application Of Hydrodynamic and

Water Quality models

15

2013

2 0 1 1

Masters’ Thesis

2 0 1 X

PhD Research

16

Water Quality Modeling in Dam

Reservoirs (Case study: Abolabbas Reservoir, Iran)

Supervisor: Prof. A. Fakheri-Fard

Advisor: Dr. Ali Moridi

Centre for Water Research

By: Behnam Zamani Gharehchaman

Application example

Purposes

Three dimensional modeling of the Reservoir to

simulate the stratification, mixing, nutrients and water quality

indexes

Prediction of released water quality for agricultural, urban and

environmental use.

Eutrophication analysis in the reservoir and defining the

temporal and spatial distribution of hypoxic and anoxic layers

Simulation of the movement of density currents in the reservoir

18

ELCOM Estuary Lake and Coastal Ocean Model

CAEDYM Computational Aquatic Ecosystem Dynamics Model

Centre for Water Research

Study Area

Application example 19

Models and Input Data

Hydro-

dynamic

Bathymetry

Structural Data

Meteorology hydrology

Temperature and Salinity

Quality

DO NO3 NH4 PO4 TSS TDS Mg

Mn TOC Ni Zn Cd Pb SO4 Ca K Na

Application example 20

Numerical Method

Named TRIM-3D, by Kassuli and Cheng (1992) this

method numerically solves the governing differential equations

C-grid by Arakawa (1997) to create the grid for Finite

Difference Method. (Semi-Implicit Finite difference)

Application example 21

Abolabbas Dam Structure

Crest Height (total): 140m Crest Length: 107m Volume: 114 mcm

Application example 23

Winter Spring Summer Autumn Winter

Hydrodynamic Model Results

Thermal Stratification

Application example 25

Winter Spring Summer Autumn Winter

Inflow

Dam Axis Spillway Cell

Hydrodynamic Model Results

Surface Temperature and Velocity Vectors

Application example 26

Hydrodynamic Model Results

Density currents simulation

Turbid Density inflow (Silt and Clay) entrains as an underflow

and is divided to 3 parts of Overflow, Interflow and Underflow | 45

days takes to pass the 3.25 km distance throughout the reservoir

Application example 27

Water Quality Results

Agricultural

Irrigation Outlet

Application example 28

Water Quality Results

Agricultural Wilcox Diagram

Application example 29

Cadmium (Cd)

Nickel (Ni)

Nitrate (NO3)

Water Quality Results

Urban Irrigation Outlet

Application example 30

Water temp

Dissolved Oxygen

BOD

Water Quality Results

Environmental Power Plant Outlet

Application example 31

Development of Hypoxic and Anoxic layers in the bottom of the

deep lakes reservoirs (hypolimnion) is very common and are

intensified by Eutrophication

Occurs by Sediment Oxygen Demand (SOD)

Causes dangerous effects on the hypolimnetic aquatic ecosystem

Oxygen Depletion

Application example 32

Conclusion

1

2

By Modeling of hydrodynamics and water quality in reservoirs we

can simulate and predict their performance in different forcing

conditions.

3

In operating reservoirs: better management

In proposed future reservoirs: adapting the structures to the

future requirements

Abolabbas Reservoir in normal operating conditions can

supply the water with very good quality for all of the purposes and

only Ni and Cd are the challenging contaminants.

4 Hypolimnetic water withdrawal via bottom outlet has a

considerable effect in reducing the strong anoxia occurring due to

drought conditions.

Application example 33

PhD Research:

Comparison between three-dimensional

hydrodynamic models and prediction of the

response of reservoirs to climate change effects

By:

Behnam Zamani-Gharehchaman PhD student in Civil and Environmental Engineering.

Supervisor:

Prof. Dr. Manfred Koch

PhD Research

Comparison of general scientific characteristics of two

powerful hydrodynamic models, as well as the advantages

and shortcoming of each in simulating the reservoirs.

Prediction of the reservoir hydrodynamic response as

well as predicting the water quality to the impacts of climate

change, i.e. global warming.

Calibration, running and validating the models for a

particular case study in Iran (Maroon Reservoir) with same

input data for both models.

PhD Research

Purposes 35

Global warming, has the potential to strongly affect physical,

chemical, and biological processes of freshwater resources through their impact on lake stratification, hydrology, and the

light availability.

PhD Research

Climate change

Reservoirs directly respond to climate change and the way they respond depends on a vast array of interactions of the

climate change effects

36

PhD Research

Climate change

In a warmer world

MORE Water-column stratification

Oxygen depletion

Nutrients inflow

Eutrophication

Algal blooms

37