Sustainable Drainage Systems
Previously, to reduce peak discharges in urban regions, hydraulic structures such as
detention storage in the form of storage reservoirs have been constructed. In recent
years, a new approach such as a sustainable urban drainage system is adopted to
manage urban floods. These structures are more effective and convenient in reducing
the peak discharges. Conventionally, these systems are used to reduce runoff
volumes from small storms. In larger storms, a sustainable drainage system can be
improved by including flow routing systems. Some of the structures commonly used
in sustainable systems are pervious concrete, green roof, and storm water detention.
Integrated Flood Management System
An integrated management system considers the drainage system as a whole,
covering all structural, hydraulic, and environmental aspects to make best use of
both existing and future facilities. In conventional flood management methods, the
different components in the hydrologic cycle are modeled individually by either
hydrologic or hydraulic components. The integrated flood management practices
provide some solutions to real-time flood control. In a conventional drainage design,
the gravity method is the only method used to route water through the system.
However, real-time control is still far from being widely practiced. To be effective,
real-time control needs reliable hardware (sensors, regulators, controllers, data
transmission systems) as well as objective and sound decision-making tools. Models
have to be used to simulate the rainfall–runoff processes to supplement the measured
data and to forecast future rainfall, as well as runoff developments, to provide the
data necessary for a decision. Radar rainfall data are important in short-term rainfall
forecasting to detect the areal distribution of rainfall patterns. The latest developments focus on the use of deterministic models in conjunction with stochastic
approaches to investigate the potentials of real-time control for given systems and
objectives. In densely populated cities, a cost-effective alternative to additional
structural control measures for regulating flooding is operating existing flood gates
using suitable controllers and control strategy (Haghizadeh et al. 2012).
Distributed Flow Routing
In distributed flow routing models, the rainfall is transformed into runoff over the
basin to produce a unit hydrograph at the basin outlet. This hydrograph is used as a
tool to produce a flow hydrograph at the outlet, and then this hydrograph is taken as
an input at the upstream end of a drainage system for storm water disposal. The unit
hydrograph is applied to storm design to yield the design flood hydrograph, and the
storm with a specific return period for flood estimation is called the design storm. In
the absence of a unit hydrograph, a synthetic unit hydrograph may be developed.
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S. Natarajan and N. Radhakrishnan
Previously, to reduce peak discharges in urban regions, hydraulic structures such as
detention storage in the form of storage reservoirs have been constructed. In recent
years, a new approach such as a sustainable urban drainage system is adopted to
manage urban floods. These structures are more effective and convenient in reducing
the peak discharges. Conventionally, these systems are used to reduce runoff
volumes from small storms. In larger storms, a sustainable drainage system can be
improved by including flow routing systems. Some of the structures commonly used
in sustainable systems are pervious concrete, green roof, and storm water detention.
Integrated Flood Management System
An integrated management system considers the drainage system as a whole,
covering all structural, hydraulic, and environmental aspects to make best use of
both existing and future facilities. In conventional flood management methods, the
different components in the hydrologic cycle are modeled individually by either
hydrologic or hydraulic components. The integrated flood management practices
provide some solutions to real-time flood control. In a conventional drainage design,
the gravity method is the only method used to route water through the system.
However, real-time control is still far from being widely practiced. To be effective,
real-time control needs reliable hardware (sensors, regulators, controllers, data
transmission systems) as well as objective and sound decision-making tools. Models
have to be used to simulate the rainfall–runoff processes to supplement the measured
data and to forecast future rainfall, as well as runoff developments, to provide the
data necessary for a decision. Radar rainfall data are important in short-term rainfall
forecasting to detect the areal distribution of rainfall patterns. The latest developments focus on the use of deterministic models in conjunction with stochastic
approaches to investigate the potentials of real-time control for given systems and
objectives. In densely populated cities, a cost-effective alternative to additional
structural control measures for regulating flooding is operating existing flood gates
using suitable controllers and control strategy (Haghizadeh et al. 2012).
Distributed Flow Routing
In distributed flow routing models, the rainfall is transformed into runoff over the
basin to produce a unit hydrograph at the basin outlet. This hydrograph is used as a
tool to produce a flow hydrograph at the outlet, and then this hydrograph is taken as
an input at the upstream end of a drainage system for storm water disposal. The unit
hydrograph is applied to storm design to yield the design flood hydrograph, and the
storm with a specific return period for flood estimation is called the design storm. In
the absence of a unit hydrograph, a synthetic unit hydrograph may be developed.
44
S. Natarajan and N. Radhakrishnan