This field report was conducted in 2008 as part of the requirements for hydrology and natural resource management course offered at the Fenner School of Environment and Society and is aimed at describing the morphological and hydrological features of several reaches of the Creek at that time.
This study is aimed at familiarizing students with sampling techniques for water quality and stream flow (inclusive flow velocity), and analysis of the data collected. The main objectives of this field observation are:
To assess the stream condition based on its water quality and loading ability of the stream.
To understand various factors that may contribute to the water quality (physical, biological and chemical properties) and stream flow (surface flow, base flow, vegetative covers, anthropogenic factors, channel, shape and structure, etc)
To compare water quality parameters in the 3 reaches, namely at constructed and instream wetland at David Street O’Connor, the concrete line section from David Street wetlands to Barry Drive Gross Pollutant Trap (GPT) and the earthen channel from Barry Drive to Lake Burley Griffin.
Table of Contents
1. Introduction
1.1.General Description of Sullivan Creek and Catchment
1.2. Previous Studies
1.3. Aim and Objectives of the Study
1.3.1. Aim
1.3.2. Objectives
2. Study Sites
2.1. Description of the Sites
2.2. Type and Form of Channel
2.3. Bed Materials
2.4. Flow Condition
2.5. Vegetation
2.6. Field Description of Topography and Land Use
3. Methodology
3.1. Sampling Program
3.2. Equipment
3.3. Procedures
4. Results
4.1 Stream Morphology (Shape and Structure)
4.1.1 Cross-sectional Measurement
4.1.2. Cross sectional measurement of channel in Reach 1
4.1.3. Cross sectional measurement of channel in Reach 2
4.1.4 Cross sectional measurement of channels in Reach 3
4.1.5. Cross sectional measurement of rectangular channels in Reach 3
4.1.6 Composition of bed and bank material (clay, silt, sand, gravel, cobbles, boulders)
4.1.7 Bed slope (as a reach mean)
4.2. Flow characteristics
4.2.1 Estimation bed roughness for Manning’s n
4.2.2 Estimation of velocity using Manning’s equation
4.2.3 Measurement of velocity
4.2.4 Measurement of discharge using cross sectional area method
4.2.5 Estimation of discharge with reference to the derived value of velocity from Manning’s equation
4.3 Water Quality
4.3.1 Water Quality Parameters in Reach 1
4.3.2 Water Quality Parameters in Reach 2
4.3.3 Water Quality Parameters in Reach 3
5. Discussion
5.1. Stream Morphology
5.1.1. Channel Shape and Structure
5.1.2. Bed and Bank Material
5.1.3. Bed slope (gradient)
5.2. Flow Characteristic
5.2.1. Disparity between direct measurement and estimation of flow
5.3. Hydrological variability of reaches in the creek
5.3.1. Hydrological characteristics of Reach 1
5.3.2. Hydrological characteristics of Reach 2
5.3.3. Hydrological characteristics of Reach 3
6. Conclusion
Objectives and Research Focus
The primary objective of this study is to assess the stream conditions of Sullivan Creek by analyzing water quality and hydraulic flow characteristics across three distinct reaches, comparing the efficacy of different channel management types, including constructed wetlands, concrete-lined sections, and natural earthen channels.
- Morphological characterization of channel shape and bed structure.
- Comparative analysis of water quality parameters (pH, EC, DO, Turbidity).
- Estimation of flow velocity and discharge using Manning’s equation versus direct measurement.
- Evaluation of the influence of land use and anthropogenic inputs on creek hydrology.
- Assessment of the ecological supportiveness of natural versus artificial channel settings.
Excerpt from the Book
5.1.1. Channel Shape and Structure
In general, there are three types of channel form observed in the channels, namely trapezoidal channel, natural irregular (earthen) channel and rectangular channel. All channels in Reach 1 and 2 constructed in trapezoidal, while the channels in Reach 1 are natural irregular (bed sections remain natural). There is, however, a small rectangular instream channel downstream of University Avenue made for observation purpose. However, as it only occupies a small portion of the bed channel, it can only be observed under low flow condition (which is the case in this assessment).
The whole trapezoidal channels upstream made from concrete and fully engineered. They are uniform in terms of size, slope and pattern within a particular reach. For example, channels in Reach 1 (alongside O’Connor Channel) are approximately 5 meters width and 2 meters depth, 30% slope and straight pattern., while channels in Rach 2 (main channels) are approximately 10 meters width and 3 meters depth, 30% slope and straight pattern. Main channel are designed bigger than sub-channel to occupy accumulative discharge from inflow points. However, earthen channel flow across the ANU precinct is much more various in terms of size, slope and pattern. The channel width, for example, tend to be larger further down stream , the slope can be inclined (30%) but often upright (see figure 14).
Summary of Chapters
1. Introduction: Provides an overview of the Sullivan Creek catchment and outlines the study's aim to familiarize students with hydrological sampling techniques.
2. Study Sites: Details the two sampling lines used in the study, specifying the location and physical characteristics of the thirteen distinct sampling points.
3. Methodology: Describes the equipment used and the procedural steps for conducting both water quality testing and stream flow measurements.
4. Results: Presents the raw data and calculations for stream morphology, flow characteristics, and water quality parameters across the three identified reaches.
5. Discussion: Analyzes the variations in stream morphology, flow discrepancies, and hydrological health, attributing observed fluctuations to environmental and anthropogenic factors.
6. Conclusion: Summarizes the study's findings regarding the high variability of the creek and emphasizes the need for comprehensive long-term assessments for effective land use policy.
Keywords
Sullivan Creek, Hydrology, Stream Morphology, Water Quality, Manning’s Equation, Discharge, Artificial Wetlands, Catchment Management, Environmental Monitoring, Canberra, Flow Velocity, Sedimentation, Earthen Channels, Land Use, Aquatic Ecosystems.
Frequently Asked Questions
What is the core focus of this research?
The study investigates the morphological and hydrological properties of Sullivan Creek in Canberra, focusing on the differences between constructed, concrete-lined, and natural stream reaches.
What are the primary themes addressed in the work?
The work covers channel structure, bed composition, water quality parameters like Electrical Conductivity (EC) and Dissolved Oxygen (DO), and the accuracy of hydraulic flow estimation methods.
What is the main objective of this study?
The main objective is to familiarize students with water quality and stream flow sampling techniques while evaluating how various channel interventions influence the ecological and hydrological condition of the creek.
Which scientific methods were employed?
The study utilized cross-sectional area measurements for morphology, the float method for direct velocity measurement, and Manning’s equation for estimating theoretical discharge.
What topics are discussed in the main body?
The main body examines the specific physical properties (shape, bed material, slope) of the three reaches and discusses how these factors, along with external inputs like urban drainage, affect water quality and flow characteristics.
Which keywords best describe the research?
Key terms include Sullivan Creek, Hydrology, Stream Morphology, Water Quality, Manning’s Equation, and Catchment Management.
Why does the study compare concrete-lined channels with earthen channels?
The comparison aims to determine how natural versus artificial settings impact the ecological supportiveness of the creek and its ability to maintain water quality.
How does the author explain the disparity between estimated and measured flow?
The author attributes the difference primarily to variables in Manning's equation (bed roughness and slope) and the limitation that direct surface float measurements may not account for velocity variations due to water viscosity at different depths.
What role do artificial wetlands play in Reach 1?
The study analyzes them as interventions designed to improve water quality through filtration and sedimentation, though it notes that external inflows like subsurface urban drainage can complicate these results.
- Citation du texte
- Omar Pidani (Auteur), 2008, Morphological and Hydrological Aspects of the Three Reaches of the Sullivan Creek in Canberra, Australia. A Student's Overview, Munich, GRIN Verlag, https://www.grin.com/document/494067
