URBAN HYDROLOGY & WATER RESOURCES

Projects:

• Wireless Sensor Networks for Continuous Monitoring of Water Distribution Systems
• Sensor Systems for Characterizing Biogeochemical Fluxes
• Near Source Contaminant Transport: Experimental and Theoretical Modeling of Sediment Clouds, and Quality of Urban Run-Off

Wireless Sensor Networks for Continuous Monitoring of Water Distribution Systems

The goals of this project are to develop generic wireless sensor network capabilities to enable real time monitoring of a water distribution network. The project will be directed towards three main applications:

1. Demonstrate the application and control of a low cost wireless sensor network for high data rate, on-line monitoring of hydraulic parameters within a large urban water distribution system. Real time pressure and flow measurements will be assimilated into hydraulic models and will be used to improve state estimation for the network.
2. Integrated monitoring of hydraulic and water quality parameters. This task will comprise a detailed evaluation of the long term performance and robustness of non-specific water quality sensors (i.e., for measurands such as pH, chlorine residual, turbidity, conductivity and dissolved oxygen), the use/development of multi-parameter sonde technologies (combined measurements in a single chip), and the application of cross-correlation techniques to interpret water quality signatures locally within the network (i.e., through local signal processing at the node level).
3. Development of systems to enable remote detection of leaks and prediction of pipe burst events. The detection of water leakage represents a critical problem in water conservation worldwide. Many older distribution networks have water losses that exceed 30% of supply. Although much smaller losses occur in Singapore (less than 5%), the development of remote leak detection capabilities can have enormous impacts on long term maintenance costs and reduce risks associated with pipe burst events. The proposed research will use high frequency pressure measurements (sampling up to 1kHz) of hydraulic transient events with a dynamic state estimation method to detect and quantify leaks, together with acoustic monitoring for accurately locating the leaks. This two tier approach will make full use of the technology developed in the first two phases of this project and will be evaluated using a controlled leak simulation.

Prototype Monitoring System for Water Distribution Network

Integrated Hydraulic and Water Quality Monitoring System

Contact PI: Andrew Whittle
Collaborators: Hock Beng Lim (NTU/Intellisys), Stephen Wong (NTU)

Top

Sensor Systems for Characterizing Biogeochemical Fluxes

Large fluxes of chemicals are transported from soils into groundwater by recharge water and, likewise, are released from aquifers to rivers and the coastal ocean by groundwater discharge. Processes occurring at the interfaces between groundwater and soils, or between groundwater and surface water, are particularly important for ecosystems because many species thrive on the abundant chemical energy at these sharp interfaces. However, the processes that occur at these interfaces are difficult to characterize because the chemical gradients are extremely sharp and can move very quickly, and these important fluxes are often poorly represented in models of global element and nutrient cycles. To quantify fluxes across these interfaces, and to understand biogeochemical transformations in these areas, we must develop measurement methods with very high resolution in both time and space. The CENSAM program will continue an existing study using a network of physical sensors (time domain reflectometry (TDR) and tensiometers) to determine water and gas flows through the rice field. By coupling this network with the appropriate geochemical sensors, the project aims to we could characterize important chemical fluxes such as methane output to the atmosphere, and arsenic accumulation in the rice field.

Bio-Geochemical Fluxes in a Rice Paddy

Field Installation

Contact PI: Charles Harvey
Collaborators: National Parks Board

Top

Near Source Contaminant Transport: Experimental and Theoretical Modeling of Sediment Clouds, and Quality of Urban Run-Off

Our parent project focuses on problems of near-source sediment fate and transport, and associated water quality degradation and mitigation, caused by dredging, land reclamation, flood control and water harvesting operations. It combines laboratory experiments and mathematical modeling studies. The experiments are looking at the behavior of dense particle clouds and plumes, under the influence of waves and currents, extending previous work done at MIT (Ruggaber) and NTU (Law). The modeling work includes the analysis and mathematical modeling of these flows, and updating their representation in standardized computer codes such as the Corps of Engineers STFATE and D-CORMIX, as well as more complex CFD codes. We will also explore strategies, involving Lagrangian tracking techniques, for representing these and other relatively small scale pollution sources into larger scale (Eulerian-based) numerical models of coastal circulation and water quality. A related component of our project involves engaging Master of Engineering (MEng) students from MIT's Department of Civil and Environmental Engineering in applied projects related to the general theme of our parent project. Up to five MEng students per year would travel to Singapore during IAP to do field work associated with their study. Our initial focus is on water quality in urban run-off within the Kranji Reservoir watershed.

The Sediment Cloud Problem

Contact PI: Eric Adams, Peter Shanahan
Collaborators: Adrian Law (NTU), Huang Zhenhua (NTU), Lloyd Chua (NTU)

Top