CONTENTS Introduction Deciding on the best system of floodplain - PDF document

3/29/2010 Dr. Mohd Ekhwan , T Assoc Professor, School of Soc. Development & Environmental Studies, FSSK.. Assoc. Research Fellow. Institute for Environment and Development (LESTARI), Universiti Kebangsaan Malaysia International Symposium on Harmonising Environmental Considerations With Sustainable Development Potential of River Basin. 24 th ‐ 26 th March 2010. Prince Hotel & Residence Kuala Lumpur CONTENTS � Introduction ‐ Deciding on the best system of floodplain land classification Aim and objective floodplain land classification, Aim and objective � Study area ‐ Langat Flooplain. � Methodology ‐ TWINSPAN & Multivariate Land Classification Technique. � Results and Discussion: Land class 1 Land class 2 & 3 Land class 4 � Conclusion 1

3/29/2010 Introduction ‐ Deciding on the best system of floodplain land classification. � What is river floodplain? Floodplains are areas adjacent to rivers and coasts susceptible to flooding adjacent to rivers and coasts susceptible to flooding during periods of heavy rain and high river flows. Typical river cross section showing floodplain area Floodplain level Bankfull Q FLOODPLAIN MEASUREMENT 2

3/29/2010 � Why we need floodplain land classification system? For managing a complex interaction between attributes (Physical & human interaction) ADAPTATION Natural Human & Environment Environment MITIGATION FLOODPLAIN SYSTEM LIMITATION IN MANAGING THE FLOODLAIN � Many land use ‐ related disciplines has numerous Many land use related disciplines has numerous classifications. � Each land ‐ management agency has several systems. � Each geographic area varies in the applicability and use of different classifications. Fractional Unit area method ‐ code – DRASTIC system ‐ North Tenness Malaysia Carolina Department of Valley District Environment Authority office 3

3/29/2010 ADVANTAGE OF ADVANCE COMPUTER GENERATING � Help planners and land managers tool to Floodplain Land Classification Model. � Reduced time ‐ consuming particularly in the stage of field data collection. � MSDOS interface DECORANA TWINSPAN ECAM, Newcastle Upon Tyne Centre for Ecology & Hydrology Wallingford, Oxfordshire MSDOS interface & Windows version AIM & OBJECTIVES � To develop the application of multivariate methods which provide a basis for field sampling. � To describe landscape variation and assess the distribution of natural and man ‐ made resources. � To provide a series of land classes. These samples enable predictions to be made about the composition of each land class and the whole catchment generally. 4

3/29/2010 LANGAT RIVER CATCHMENT � Ca= 1815 km2 � Total stream length = 2530.46 km � Size of floodplain area = 508 3 km2 � Size of floodplain area = 508.3 km2 � Drainage density = 1.39 � Stream order = 5 Rainfall pattern 5

3/29/2010 Drainage density (1.39) TWINSPAN & Multivariate Land Classification Technique � The classification of the floodplain is based on floodplain areas mapped in 1995 by the Drainage and Irrigation Department (DID) on the basis of the extent of past floods. D (DID) h b i f h f fl d � The Langat floodplain was divided into 508 one ‐ kilometer grid squared. � TWINSPAN ( Tw o ‐ way IN dicator SP ecies AN alysis) was used to produce the multivariate classification. � 54 attributes representing: topography, geology & soil, vegetation, hydrology & geomorphology, human artifacts. � Public domain: Window WinTwin (Version 3.2) at: http://www.ceh.ac.uk/products/software/CEHSoftware ‐ DECORANATWINSPAN.htm 6

3/29/2010 54 map attributes. Data Data from includes topographical one in 508 km features, geology and soil, squares vegetation, hydrology and human artifacts. Characteristic s from 508 km CLASS 4 TWINSPAN : Indicator species analysis. Classification into groups of square. CLASS 3 55 divisions of 42 Land classes CLASS identified by 2 TWINSPAN (This TWINSPAN (Thi study only analyse based on 4 land classes) CLASS 1 Characterize the classes by their constant and selective attributes. RESULTS: TWINSPAN OUTPUT � From the original 508 grid squares= g 5 g q a. 144 were classed as land class 1, 243 as land class 2, b. 104 as land class 3 and c. d. 17 as land class 4. � In general, the distribution of the Langat floodplain can be d v ded divided into 3 general land classes: to 3 ge e a a d c asses: a. upland areas (land class 1), b. intermediate or transitional between lowland and upland areas (land classes 2 and 3) and lowland areas (land class 4). c. 7

3/29/2010 MULTIVARIAT LAND CLASSIFICATION N 0 4 km LEGENDS Land class 1 Land class 2 Land class 3 Land class 4 Distribution of the Langat Floodplain land classes CLASS 1 CHARACTERISTICS � Upland map characteristics predominate in this class, which is located on the upstream valleys of Langat River and Semenyih River. d S ih Ri � Mostly the entire of the Hulu Langat District located within this land class. � The landscape is influenced by Titiwangsa Range, which surrounded with 100 ‐ 200m and more 200m contours. � Topography is steeply sloping where it is dominated by serdang series serdang series. � The present of this soils indicate that the areas are vulnerable to surface erosion. 8

3/29/2010 CLASS 2 & 3 CHARACTERISTICS � This is intermediate between lowland and upland classes. � This type of land classes contains all the major urban Thi t f l d l t i ll th j b areas: Kajang, Bandar Baru Bangi, Cheras, Dengkil and Semenyih. � Geologically consists of Stratigraphy: Quaternary was dominated in the land class 2, which is about 47.6 per cent from the total grid squares. � In the land class 3, cultivation mainly oil palm estates I h l d l l i i i l il l are predominant. It covers about 19.3 per cent from the total grid squares. CLASS 4 CHARACTERISTICS � This is the lowland land class of the Langat floodplain and down stream of the Langat River. g � It is coastal, generally close to intertidal sand or mud and is found particularly around Banting and Klang towns. � Topography is fairy flat although short steep slopes are common in areas of Jenjarum and Bukit Cheeding. � Wetland forest, mainly mangrove (Bakau), local species such as nipah and gelam are predominate. 9

3/29/2010 CONCLUSION � The Langat Floodplain multivariate land classification provides an integrated, holistic stratification on which id i d h li i ifi i hi h minimum affective field sampling programs can be based. � More importantly, it can also be used as a unifying system of classification, providing a common framework for many users, including environmental management, forest management, urban management and nature conservation. i � In conjunction with standardized methods of field survey, it provides a flexible, multipurpose approach to assessment and monitoring of natural and man ‐ made resources. Thank you Special Thanks to: Universiti Kebangsaan Malaysia, Wallingford Software (UK) & Environmental Centre and Management (ECAM), Department of Civil Engineering University of Newcastle Upon Tyne which provide funding, computer and software facilities during the 1 week 2009 summer training on Floodplain Modeling g 9 g p g Workshop. 10