Abstract: Most people today are aware that global climate
change is not just a scientific theory but also a fact with worldwide
consequences. Global climate change is due to rapid urbanization,
industrialization, high population growth and current vulnerability of
the climatic condition. Water is becoming scarce as a result of global
climate change. To mitigate the problem arising due to global climate
change and its drought effect, harvesting rainwater from green roofs,
an environmentally-friendly and versatile technology, is becoming
one of the best assessment criteria and gaining attention in Malaysia.
This paper addresses the sustainability of green roofs and examines
the quality of water harvested from green roofs in comparison to
rainwater. The factors that affect the quality of such water, taking
into account, for example, roofing materials, climatic conditions, the
frequency of rainfall frequency and the first flush. A green roof was
installed on the Humid Tropic Centre (HTC) is a place of the study
on monitoring program for urban Stormwater Management Manual
for Malaysia (MSMA), Eco-Hydrological Project in Kuala Lumpur,
and the rainwater was harvested and evaluated on the basis of four
parameters i.e., conductivity, dissolved oxygen (DO), pH and
temperature. These parameters were found to fall between Class I and
Class III of the Interim National Water Quality Standards (INWQS)
and the Water Quality Index (WQI). Some preliminary treatment
such as disinfection and filtration could likely to improve the value of
these parameters to class I. This review paper clearly indicates that
there is a need for more research to address other microbiological and
chemical quality parameters to ensure that the harvested water is
suitable for use potable water for domestic purposes. The change in
all physical, chemical and microbiological parameters with respect to
storage time will be a major focus of future studies in this field.
Abstract: Extreme rainfall frequency analysis for Meteorological Sub-Division 4 of India was analyzed using L-moments approach. Serial Correlation and Mann Kendall tests were conducted for checking serially independent and stationarity of the observations. The discordancy measure for the sites was conducted to detect the discordant sites. The regional homogeneity was tested by comparing with 500 generated homogeneous regions using a 4 parameter Kappa distribution. The best fit distribution was selected based on ZDIST statistics and L-moments ratio diagram from the five extreme value distributions GPD, GLO, GEV, P3 and LP3. The LN3 distribution was selected and regional rainfall frequency relationship was established using index-rainfall procedure. A regional mean rainfall relationship was developed using multiple linear regression with latitude and longitude of the sites as variables.
Abstract: Rainfall data at fine resolution and knowledge of its
characteristics plays a major role in the efficient design and operation
of agricultural, telecommunication, runoff and erosion control as well
as water quality control systems. The paper is aimed to study the
statistical distribution of hourly rainfall depth for 12 representative
stations spread across Peninsular Malaysia. Hourly rainfall data of 10
to 22 years period were collected and its statistical characteristics
were estimated. Three probability distributions namely, Generalized
Pareto, Exponential and Gamma distributions were proposed to
model the hourly rainfall depth, and three goodness-of-fit tests,
namely, Kolmogorov-Sminov, Anderson-Darling and Chi-Squared
tests were used to evaluate their fitness. Result indicates that the east
cost of the Peninsular receives higher depth of rainfall as compared
to west coast. However, the rainfall frequency is found to be
irregular. Also result from the goodness-of-fit tests show that all the
three models fit the rainfall data at 1% level of significance.
However, Generalized Pareto fits better than Exponential and
Gamma distributions and is therefore recommended as the best fit.
Abstract: Rainfall records of rainfall station including the
rainfall potential per hour and rainfall mass of five heavy storms are
explored, respectively from 2001 to 2010. The rationalization formula
is to investigate the capability of flood peak duration of flood
detention pond in different rainfall conditions. The stable flood
detention model is also proposed by using system dynamic control
theory to get the message of flood detention pond in this research.
When rainfall frequency of one hour rainfall duration is more than
100-year frequency which exceeds the flood detention standard of
20-year frequency for the flood detention pond, the flood peak
duration of flood detention pond is 1.7 hours at most even though the
flood detention pond with maximum drainage potential about 15.0
m3/s of pumping system is constructed. If the rainfall peak current is
more than maximum drainage potential, the flood peak duration of
flood detention pond is about 1.9 hours at most. The flood detention
pond is the key factor of stable drainage control and flood prevention.
The critical factors of flood disaster is not only rainfall mass, but also
rainfall frequency of heavy storm in different rainfall duration and
flood detention frequency of flood detention system.