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__. -. _ IU- . pL . _I ta WS L1 --tKt 13010Relation between Antecedent Rainfall or Rainfall Amount with the Occurrence of L. andslidc in I Inivcrsiti Tcknologi ITTRONAS
BY
Mahd Arit'lein Wan Mahd 1)zulkitli
Dissertation suhmittcd in partial tiilfilmcnt of the rcquircmcnts fur the
Bachdur of' Engineering (I Ions) (Civil Engineering)
Jt 11.
Y
2aK)Univrrsiti Trknulogi I'1: TItONAS
Bandar Srri lskandar
31750 'I'ranoh
('l: lt l lf l('A I ION OFAPPkOVAI.
Rotation Between Antecedent Rainfall or Rainfall Amount With The Occurrence of
Landslide In Univorsitl Toknologi PETRONAS
by
Mahd Arif bin Wan Mahd I)zulkifli
A project dissertation submitted to the Civil Engineering Programme llniversiti 'I'ekm)logi I'I? 'IR()NAS in partial fulfilment of* the requirement for the
BA('IIEI. OR OF IEN(; INI: I: RIN(; (lions) (CIVIL. EN(; INEERIN(; )
Approvod by,
1, ",, (ý.
(Ih. jtcfýur k I1huiyen)
I INIVI: RSI 1'1 '1'I": KN()l. (); l PF'1'K()NAS IRONOII, PI: RAK
('I: R I'II I('A F ION OF ORIGINALITY
his is to certify that I am responsible fir the work submitted in this project, that the original work is my own except as specified in the references and acknowledgements, and that the original work contained herein have not been undertaken or done by unspecified sources or pcn'ons.
A('F: NOWI, F; U(: MF: N'I'
birst and forcmost, I givc thanks and praisc to Clod fier I fis guidancc and blcssings throughout the cntirc course of my study.
I wish to cxprcss my grutitudc to Dr Kczuur Kahman I3huiyan, for his guidancc and support throughout complcting my Final Ycar I'mjcct in the I Jnivcrsiti 'I cknologi
Pctronas Civil E: nginccring I)epartmcnt. Ills knowlcdgc is vital for the project that I had
worked for. Without hclp from him, this Final Ycur Project may not hie that mcaningful and successful.
Circatcst apprcciation is also cxprcssed to the following individuals. l)r. llasnain. Miss Nurul liu na, Mr Kalai, Mr Mcor. I)r. Indra Sakti. Dr Sycd Rahamm, and all staffs of Civil Enginccring I)cpartmcnt.
My acknowledgement would be incomplete without giving credit to t Jnivcrsiti Tcknologi I'ET tONAS. especially Civil Engineering Department which has equipped
me with essential skills for self-lcuming. Its well-rounded graduate philosophy has proven to be useful in the industry.
Finally. I would likc to thank my family. 'l ticy havc been a wonderful source of cncouragcmcnt and joy to me and also not to forgct the fellow friends who's their help was a trcmcndous gift to mc. May God bless all of uv and only III.. the Almighty could repay all my debts to them.
Abstract
This study is presented to examine the relation between antecedent rainfall or rainfall
amount with the occurrence of the landslide in llnivcrsiti Tcknologi 1'1": l lt()NAS
(IYTP), Trunoh, Perak. the landslide had occurred near the Civil Engineering Block, Block 13, and caused a slight damage to that area. It was said that there were heavy rains for a few days before the event took place. Thus there is some possibility that the event might be caused by the rainfall. This study basically is to find out the cflcct of the rainfall (antecedent rainfall or rainfall amount) toward the occurrence of the landslide. The data of the rainfall for 2-year period had been obtained from the Hydrology and Water Resources of Department of Irrigation and Drainage Malaysia (I)II)) in order to perform this research. '11 c data has been analyzed one by one and the result of the analysis shows the antecedent rainfall factor plays more important role than the triggering rainfall in this particular case.
TABLE O ('ON"TFN'1'ti AKti'I"kAc'r.
...
ic "IiAP'rFR
l: IN7'It()1)ii("i'1()N .i
1.1 Background of Study .I 1.2 1'rohlcm Statcmcnt 51.3 Objcctivcs und Scopc of' Study 7
CHAPTER 2: LITERATURE REVIEW
.
x
('IIAPTER 3: MEI'Iü)IK)1. (K; Y
.... 11
3.1 Prujcct Activities
... 11
3.2 Gantt ('hart and Kcy MilcYtcmc
. 18
('IIAPTF: R 4: RESULTS AND DISCUSSION 20
('IIAPTE; R S: ('()N('I, I1ti1()N ANI) RF: ('()MMF: NDA'I'1()N 28
REFEREN('ES ... 29
List of Figures
Figurr I
.I. Danusgcs cuuscd by landslidc at Nukit Anturuhangsa.
Figurr 1.2. Right vicw of I. andslidc in IJnivcrsiti 'I'cknologi PI: TRONAS. Figurr 1.3. Front vicw of Landslidc in (Jnivcrsiti 'I'cknologi PI . 'I RONAS. Figure 1.4. I. ci1 vicw of l. andslidc in I Inivcrsiti 'I'cknologi ITTRONAS.
Figure 4.1. Monthly rainfall in 2007 at (a) Rumah I'am Bola (h) Ladung Nallu Figurc 4.2. Daily rainfall data in (ktobcr 2(K)7 fir (a) Rumah l'am Motu (h) l. adang Nalla
Figurc
4.3. Accunwlutivc of I I-days ruinfull
fierthe month
of(U)Junc 2007 (h) July
2007 ((; ) Octohcr 2007
at Kunluh
Mull Ik til.Figure 4.4. Accumulative of I I-days rainfall for the month of(u) June 2(K)7 (h) July 2007 (c) (ktobcr 2007 at Ladung Nalla
Figure 4.5. The highcst anteccdcnt rainfall with elapsed timc of* I-day, 3-day, 5-day. 7- day, 9-day and II -day at Rumah I'm Rota and l. adang Nalla through out of 2007.
List of Tablets
'fable 3.1. Milcatonc for the Firm Scmc%tcr of 2-Semcstcr Final Ycar Project
'fable 3.2. Mile. onc for the Second Semester of 2-Semester Final Year Project
Chapter 1: Introduction
1.1 Background of study
Nowadays, landslide is a common incident happened in many Malaysia and most of' the tropical area in the world. For lur't few months, there were several landslide cases were reported in media. The latest was the tragedy of massive landslide that happened at Taman Bukit Mcwuh and Taman Bukit t ltarna in Ihukit Antarahungsa, Kuala Lumpur.
The catastrophe had destroyed many houses and properties around that residential tutu as shown in Figure I. 1. It also had killed many innocent people who live there. It was said that the main factor of this catastrophc was due to the heavy rain.
.. I-. -
FiKure" I. I I)amap-. +' cuumrd hY landslide ul Ilukil Anlaruhan};. +a
The 13ukit Anturubangxu landslide is actually the third to twcur in the Klang Valley in a week. On Nov 30,2008, two sisters, were killed in a landslide which hit their bungalow in Ulu Yam Perdana, Uumbak. On 'l'hur day, a landslide in Julun Semantan caused part of the retaining wall of a car park situated between two buildings to collapse, burying six cars and damaging five other vchiclcs. 'lhcsc landslides arc believed to have been caused by movement of underground water and a condition made warsc by the heavy rainfall in recent weeks.
Actually there were more landslides had been occurred especially during the raining season. On 1kv 11,1993, one of three blocks of the 12-storey Highland 'l'owers apartments collapsed killing 48 people.
This kind of tragedy can not afford to he happened again in the future because besides causing physical damages, it also can cause economic loss and this will give had impression to the stability of national administration. further action need to he taken and this has to be started with the investigation to find the major factor that leads to the landslide problem.
11mically, a landslide (or landslip) is a geological phenomenon which includes a wide range of ground movement, such as rock falls, deep failure of slopes and shallow debris flows, which can occur in offshore, coastal and onshore environments. Although the action of gravity is the primary driving force for a landslide to occur, there arc other contributing factors affecting the original slope stability. Normally, pre-conditional factors build up specific sub-surface conditions that make the area or slope prone to failure, whereas the actual landslide often requires a trigger before being released.
There are many factorn that can contribute to the landslide events. Actually, landslides arc caused when the stability of a slope changes from a stable to an unstable condition. A change in the stability of a slope can be caused by u number of factors, acting together or alone. These arc -*)me of possible causes that can lead to the landslide events; (; oologkal causes
"
Weak materials
" Scnsitivc materials
" Weathered materials " Sheared materials" Jointed or fissured materials
" Adversely orientated di. *; ontinuitics
" I'crmcability contrasts
" Material contrasts
" Rainfall and snow full
Morphological causes . Slope angle "l iplift " ltctx)und " Fluvial crosion " Wavc erosion " Glacial crusion
" l: rosion of lateral margins
" Subterranean crosion . Slopc loading . Vegetation changc Physical causes " Intense rainfall " Rapid wx)w mclt " Prolonged precipitation " Rapid drawdown " FArthyuukc " Volcanic eruption " thawing "I recce-thaw " Shrink-swell
" Ground water changes
" Soil parr water pressure
Surface runof'f' Seismic activity Human causcs " Excavation " I. owding " Drawdown " Lund we changc " Watcr manugcmcnt " Mining " Quarrying " Vibration " Watcr Icakugc "I )clorestation
As mentioned helorc, most of the landslides tragedies in Malaysia wcrc found occurred during the raining seasons. 'thus there is high possibility that the main cause for the landslide is coming from the rainfall.
In this study, the rainfall (antecedent rainfall or rainfall amount) will be taken as the major factor to examine the cause for the landslide. It is hoped that it will help the authorities and all the related departments to come with some ideas in order to prevent this landslide problem or at least lessen its side effect.
1.2 Problem statement
Previously, a landslide had been occurred in llnivcrsiti '1'rknologi I'E1'RO NAS
(till') at the hilly area near Block 13. As shown in Figure 1.2 1.4, the landslide was
not really dreadful but yet it was still significant to engineering field as if there arc no further action taken, this tragedy might be happened again and may be next time the impact will he greater.
Figure /.?. Kight view q/ lsmcLslidr.
l YKtirr !. 4. Left view of l. cuiclslic1e.
'There arc many factors contribute to the landslide such as rainfall. initial water table location, geometry of the slope, and etc. It was said that a tcw days before the accident was happened, there was ruining all day long. So, there was a possibility that the landslide was caused by that antecedent rainfall. A research will be conducted to find out is there any relation between the rainfall (antecedent rainfall or rainfall amount) with the slope stability that has made the landslide to he occurred.
1.3 Objective and scope of study
The objective of this study is to examine the relation between antecedent rainfall or rainfall amount with the occurrence of the landslide near the Block 13 in llnivcrsiti
Tcknologi PE'TRONAS (1 This study will cover the collection of rainfall data, data
modeling and rainfall analysis.
This study only coven the effect of the rainfall to the landslide without considering any other sail properties factors.
Chapter 2: Literature
Review
As been mention bcfi)re, rainfall is one of the major factor that can cause landslide to take place. But it is still confusing on what kind of nainliill that can really cause this incident. Although the correlation between rainfall and landslides is widely recognized,
there has been some debate as to the relative rok of antecedent rainfall and the
triggering rainfall.
In the scope of landslide study, the antecedent rainfall is referred to the rainfall in the days right away preceding a landslide event. The triggering rainfall mcanwhilc is referred to the rainfall that falls at the time that the landslide occurs.
'ileac are already some researches have been made to we and prove the efTect of the antecedent rainfall on the slope stability. The researches show that the landslide might be occurred due the amount of the rainfall during the event, the antecedent nainf4l1 or even including both of the factors.
Earlier, according to Brand (1984) through the researches made by him in Hong Kong. it is suggested that the antecedent rainfall was not a major factor to Iced the landslide. Most of the landslides happened due to the short duration rainfall with a very high intensity. It was found that the 70mm/h of rainfall intensity would he enough to cause landslides in Ilong Kong and a significant number of failures could be expected if
the rainfall exceed 100mm/day. 'lice limited influence of antecedent rainfall on landslides in Ilong Kong was due to the high permeability of the local soils (Brand. 1992).
In Papua New Guinea, landslides might be happened if'thc rainfall intensity exceeds 70mm/h, as being suggested by Murray and Olsen (191K) and most of the major landslides occurrcd after 24 hour rainfall of 125mm. Major incidents would not be expected to ocxUr until the rainfall reaches or exceeds the intensity of 1(X)rnm/day.
Pitts (1985) also concluded that the cffcct of'thc antecedent rainfall toward the slope stability in Singapore was not too much significant.
However, Tan et al. (1987) re-examined Pitt's conclusions and suggested the otherwise; the antecedent rainfall could be significant in eflccting the slope stability. Later. Chatterjea (1989) also came out with same conclusions. For the study case made by Wei ct al. (1991) at I3ukit Batok landslide in Singapore, it was found that the landslide occurred after a period of heavy rainfall but during the day of the landslide, there was no rainfall. This showed how the antecedent rainfall may afket the slope stability.
According to Rahardjo ct ul. (2(X)1), the landslides that had occurred at Nanyang Technology University Campus in Singapore were due to the antecedent rainfall. From the investigation they made, it seemed that the antecedent rainfall during the five days before the event was significant in causing these landslides since other rainfall events of* similar magnitude (hut with less antecedent rainfall) did not cause landslides. In that study, any daily rainfall greater than 90mm must be followed by a 5-day antecedent rainfall exceeding 00mm first before it can initiate the landslides.
Unlike other researches, instead of using S-day period, I . umh (1975) used a 15-day
period to quantify antecedent rainfall fiºr I long Kong. It was still cf'cctive to prove the effect of the antecedent raintirll towards the slope stability. Later, the way he used was adopted by 'fan et al for their study on the landslide in Singapore. I lowever, ('hartteijca (19X9) suggested that such a long period might be inappropriate for the rainfall pattern in Singapore and he adopted a period of 5-days.
Ilowever, in the other research, also by Rahardjo ct al. (2(x)8), to identify the role of some controlling parameteni (particularly the role of antecedent rainfall) in inducing instability of a homogenous soil slope, it is found that the significance of the antecedent rainfall depends on soil permeability. Yes, it is true that the effect of anteccdcnt rainfall depends on sail permeability but for the investigation at area which have slightly same soil permeability; this parameter still can be considered as the main cause fir the landslide.
By taking these journals as reference and main idea, a research will he done to identify the ctlcct antecedent rainfall to the landslide that had happened at tinivcnciti 'l cknologi l'l TRONAS ((J*I'P) ccunpus.
In enginccring point of view, regardless the role of the soil permeability, the antcccdcnt rainfall actually drives an incrcasc in pore water pressures within the soil. 'T'his fluid pressure provides the block with buoyancy and later reducing the resistance to movement of the soil. It is happened when the slope fills with water. The fluid pressures then act down the slope as a result of groundwater flow to provide a hydraulic push and
dccrva,, c the stability and further causing the landslide.
For examining the connection between antcvcdcnt rainfall or rainfall amount with the landslide occurrence, the rainfall data at the event area need first to be presented in graph. It is to case the observation ofthe data.
71hc graph needs to he studied first and then identify the major storm events. If it is found that then: is any daily rainfall that exceeds the rainfall record at day that the landslide was happened, but yet still produced no landslide, it means the landslide might he due to the antecedent rainfall. The accumulative rainfall tier a certain period prior to a heavy-storm day also can be considered as the factor if the cllcct of antecedent rainfall can not be proven.
After the cause has been identified. further study on the soil properties ulso can he done to give more information about which types of u )il might be affected to those factors.
Chapter 3: Methodology
Iktcnniruition of' the cfkct of the antecedent rainfall toward land slide is to be done. the resrnrchcs will be made through the internct, books and reliable articles or journals to collect all available information concerning the topic on the cflcct of' antecedent rainfall on the slope stability. 'l'hc collections of technical details regarding various
rcscarc: hcs on the subject will he used to implement and accomplish this project within
the timcframe given.
3.1 Project activities
This pn)jcci will incimic the following activities:
3.1.1 Acquiring Rainfall Data
'l'o do this investigation, a data of ruinfiill records at the landslide area, fir 2 years period at bast, is needed. The rainfall records from January 2(x)7 through January 2009 will be studied to identify major storm event as the landslide is assumed to fail early in
2009. The rainfall data needs to be gathered from reliable source so that a convincing result can be produced. The data can be obtained from:
"I Iydrology Department oft niversiti Teknologi PI -A RONAS (UTP) Civil
E: nginccring Department
" Department of Irrigation and Drainage Perak
Ilowcvcr, thosc dcpartmcnts can only prnvidc at most up to one wcck pcricxf of rainfall data. For longcr pcricxl data rrquirrmcnt, it nccds to be obtaincd from I lydrology and Watcr Rcaourvcs of I)cpartmcnt of Irrigation and I)rainagc Malaysia (I)II)).
Fhe prcx; ctiiurr uf*upplying hydrological data from the 1)II) is its folluws-.
l) The applicant is requested to fill in the appropriate application firms (Form I)1.1
(sec Appendix I) or Form I)1.2) which arc available in the 1)11) wchsitc.
hap. h 2o. water. gov. mv. It is recommended that applicant refers to 1)11) station inventory in order to determine the stations and period of data availability required during the pruccss of filling-up the fire.
2) "Ihw applicant has to either tax the completed form to the given address or send it via E-mail. :
3) Tbc application usually will bc approved in one wcck.
As thcrc is no spcc. itc ruin guugc station placcd at the occurrence placc. the rainfall
data from the ncnrest rainfall stations arc rcqucstcd. 'Ihcrc arc seven rainfall stations Iocatcd around tinivcrsiti 'I'cknologi PI: 'I'RONAS which arc;
1) 4308092 2) 44(w()90 3) 44(')091 4) 440121 5) 4410120 6) 4410122 7) 4410123
'Ibcfe is posuibility that then: might he some data missing in the provided data f mmi the I)1I). If this is happened, the estimation of the missing data needs to be calculated.
1C it is given that the annual precipitation values, l'i, P2.1111.
..., I'm at neighbouring M
stations I. 2.3...., M respectively, the missing annual precipitation 1'w at a station X
which is not included in the utx>vc M stations can he fand by using some simple calculation.
If the normal annual prccipitations at various stations arc about IO% of the normal annual pmcipitation at station X. thcn arithmctic avcragc pro cdurc can be uscd to
estimate the I'.. I
P. - --- (Hi 4H: f ... +F'm) M
If the narnnal precipitations vary significantly, thcn P% is estimated by using normal ratio mrtbcxl, bywcighing the precipitation at the various stations by the ratios of nomuil annual precipitations.
N%
--- ((f't/Nt)+(f'2/N: )+ ... +(f'm/Nm)) M
lksidc the rainfall data, the date of the occurrence of the landslide also nerds to he obtained. the date is very important in order to further this study. '11tc detail can be obtained from the Property Management and Maintenance I)cpurtmcnt of Univcrsiti
3.1.2 Modeling the Rainfall Records
Aftcr gathering the data from all those stations, the details will be modeled and prrscntcd by using hyctograph. According to K Subramanya, a hyctograph is a plot of
the intensity of the rainfall against the time interval. It is usually represented as a bar chart. It is a very convenient way to show the characteristics of a storm.
I1x»c data taken from the rain gauges actually only represent Ix+int sampling of the areal distribution of a storm. "Illus. in order to convert the point rainfall values at the various stations into an average value over the catchmcnt area, these three methods can he used,
1) Arithmctical-Mcan Method
2) 'I? wiswn-Mcun Mcthtxi
3) Iwhyetal Method
AridunrNcul-Mrun Mr#kxl
"Flits technique calculates areal precipitation using the arithmetic mean of all the point or areal mcasurcmcntx considered in the analysis. If l'i, l'z, ..., Pi, ... Pn are the rainfall values in a given period in N stations within a catchment, then way to calculate the value of the mean precipitation or the cflcctivc depth 1'c over the catchmcnt by the arithmetic-mean method is as follow;
1) Sum the precipitation (11) at each station (1 through n).
2) Divide the sum from (1) by the total number of stations (N). This will yield the
etlcctive depth of precipitation (11. )
(HI+1': +... +Pi+... +I'n) N
PC
- --- -( I/N) 2. I'i
N ri
I hei. ssen-Alean Alethod
This is another graphical technique which calculates station weights based on the relative areas of each measurement station in the Thiessen polygon network. The individual weights are multiplied by the station observation and the values are summed to obtain the areal average precipitation. The procedure of determining the weighing area is as follows;
I) Connect each station to c4ch ncarby station with a straight linc. T hcsc lines cannot cross and should connect only the nearest stations. If'done correctly, you will form several triangles.
2) Each Icg of the triangics formcd in (1) is thcn hisectcd with a pcrpcndiculur linc,
thw farming polygon. ýc around each station. Draw over the ling defining the
polygons with a RED pencil to avoid confusing them with other lies you have drawn.
3) Using an appropriate method calculate the land area (A) represented by each polygon (I through n) and record this area fir each station.
4) Also c: alc: ulutc the total area (At).
5) ('alculatc the cffcctivc depth of precipitation (Ile) by the following formula:
Pi(Ai); P: (A2)+... Il'n(An) N A+
Pc - --- IN ..
AIfAY0
... +An rj
lsuhºerul , tJrthuc!
his is a graphical technique which involves drawing estimated lines of equal
rainfall over an area based on point measurements. The magnitude and extent of the resultant rainfall areas of coverage are then considered versus the urea in question in
order to estimate the areal precipitation value. The procedure of determining the
effective depth of precipitation is as tiollows;
1) The measured precipitation is recorded next to each station.
2) Using these values, neatly construct (n) isohyctals lines (contour interval -- 2").
3) ('alculate the area (A) between adjacent is)hyctal lines (1-2,2-3,..., (n-1)-n).
4) Also calculate the total area (At).
5) Calculate the effective depth of precipitation (l'c) by the following formula:
('I. (/\ )t('z"3(A2. »$.... +C(n"iº-n(A(n"I). n) H. ý ---
Ai
where C- depth of precipitation represcntcd by adjaccnt isohyetal lines (1-2.2- 3,..., (n-1)-n)
3.1.3 Analyzing Data
The data in the hyctograph will then he observed and analyied in details one by one. From the observation nutdc, the result will show exactly either the antecedent rainfall really causes the failure of the slope or not.
Let say it'll is found timt there is any daily rainfall that exceeds the rainfall record at there day that the landslide was happened, but yet still produced no landslide, it means
was possibility that the landslide was occurred due to the antecedent ruinf trll. The accumulative rainfall for a certain period prior to a heavy-storm day also can be considered as the factor if the effect of'antecedent rainfall can not be proven.
3.2 (; ants ('hart and Key Milestone
Table 3.1: Milestone for the First Semester of 2 -Semester Final Year Project
No Iktsils/Wcek 1 2 3 4 5 6 7 8 9 10 II 12 13 14 IS 16
1 ticlcction of* I'rojcca
Iopic
- Kcscurch on Topic
- Confirmation of" Foplc
Srlccticm
2 I'rclimiruu}" Rcscurch Work - I. itcniturc rcvicw - lacntityinl; mcthtxis uscd ý Submis. tion of I'rclimiruuv and ý - I'nosress Kqx)rt 4 I'rojcc: t Work - Acquiring Dula b Scmiruirot' FYI, 17 I'nýjcct work continuc
- AcquirinE t)utu
7 7 7 7
It Submission of' Intcrim
- Kcjxºrt Firurl Drall 0 9 Oral I'rcscntution " 10 Submission of Interim " k )rt ý tiug$cstcd milcstanc 1'nvcss 18
Table 3.2: Mdestonc for the Second Semester of 2-Semester Final Year Project
No. I)ctaW Wcclk 1 2 3 4
,i
6 7 8 9 10 111 [12 13 14I I'rojcct V`'ork ('ontinur
nl(xlrIinE 1). ta
? Seminar (contpubiory)
; Submission of I'rt)ºrc? kt It )rt I
4 I'nlcct «ork continuc
Arurlýiin ý 1)utu -
5 Poster Exhibition
tiuhmixxion of Uixx-nation sofft bound)
7 Oral 11'rcscntation
K Submission of* I'rojcct Disscrtation (I lard Bound)
ý tiuggcNctrd milrstunr
Chapter 4: Results and Discussion
I'rOUI out of 7 the rainfall stations placed near the llniversiti 7'eknologi PE'FRONAS (IYFI'), only 5 of them have the required details (daily rainfall data for 2007-2009) which arc;
" 4309092 Rumijh Pam Bola
" 4311(X)1 Pcjahat I)acrah Kumixu
" 44()y(K)1 itumah Pam Ku1wnK i luji
" 4409121 Ladung Nallu
" 4511111 Politcknik lingku Omar
And from these 5 stations, only the data from 2 stations have been picked to
prex: ccd with the project which are 43(9092 and 4409121 as the location of the stations
are the nearest one to the till'. The daily rainfall data from those two stations are shown
in the appendix section (Appendix 2).
As the landslide was occurred on 23 Id October 2(X)7 (according to Property Mnnagcmcnt and Maintenance 1)cpartment of' I Y111), only data from year 2007 was taken into consideration to be studied and analyzed in order to identify the major storm events at the landslide spot as the result that produced by later data (2(X)8 and 2(x)9) will give no relative effect to this research.
Afire transferring all the rainfall data from Rumah Pam 134uta and I. adang Nails
into proper table, the data then was analyzed in detail. '['he more specific data (such as daily rainfall data, monthly rainfall data, accumulative of I1-days rainfall data and s) on) were calculated one by one and each results were platted in hyctogruph or bar chart. This is to ease the data analyzing process.
From the observation, it was found that the maximum monthly rainfüll through out the year, at Rumah Pam liota, was 403.0 mm in October while at Ladung Nulla was 350. Omm, also in (ktober. From this fact, it can be assumed that the rainfall can be rated as one of the major factor for this landslide. The monthly rainfall records for 2(x)7 at both stations are shown in Figure 4.1.
Total Rainfall at Rumah Pam Bota (2007)
MorNJhfy Rdnhll (mm) 4500 4000 3w o 3w o 2500 qpp 0
2105
217"5, i.,,, n-
r-,
M288.0
228.0 403.0 ý """' 13A. 5 134,6 160 0 95.5 1000 86,6ýý
sa0
91 00
103 ri ý... 1234567HU 10 11 12 MonthTotal Rainfall at Ladang Nails (2007)
Yo. y Rak*hd (mm) 400 0 350 0 3000 29 35 260 .6 326.0 350,0 298.0 244,0 iau ut slt '0 ý 200 0' 181 0 1600
61
1060 116.0 117. Q 1000 67,0boo
nn VV ! I73 4561B8 10 11 12 MonthF 1Xurr 4. /. Munch/v
rai, ell in 2007 at (a) Rumah /'am Bola (h) LadünX
Nulle
During the period before the event took place which was on 23rd October, there were several days in which the daily ruinfull exceeded 70mm; 4 days at Rumah Pam
13ota, these were 93.5mm on 2I" January, 113.0mm on 14th June, 103.0mm on 26th July
and 79.0mm on 22"d (ktobcr, while at Ladung Nalla, it got 2 days. 79.0mm on 15th January and 7 I. Omm on 23 `d July.
'1bo c rainfalls wcrc sufficient to causc a landslide on those days but thcrc was no landslide occ: urrrd. More over, during the incident, the rainfall at l. adang Nalla station was very low which was only 9.0mm and even at Rumah Pain Bola, there was no rainfall at all. Figure 4.2 below shows the daily rainfall in October at both rainfall stations.
Dally Rainfall (October 2007) at Rumah Pam Bota
900 _eoo ý 700 -wo ao0 400 ý200 300 100 00 600 ýsoo 400 ý 300 20 0 100 00 -
Goo
400 150 70 80®R o
12]456189 22.00
790 aoo 2600
150
ý 6®
610 24.0 10 11 12 13 14 15 1 t1 11 15 1Y 20 71 77 23 24 75 28 21 25 29 30 31 TMne, f (dhn)Daily Raitall (October 2007) at Ladang Nails 480
70 110
11i4°I
6.0 DO 1101. ' .0O
./
10n 101
1234D91f! 0 loll 17 1J 14 15 It1 11 10 1p 20 21 7i 2: 1 74 ib itl "I/ 2tl 2fi JO J1 Ttrne, t (days)
Figurr 4.2. Ikiihy rainfall duly in (A-tuber 007 für (a) Ilumuh l'um lima (h) l. adang Nulle
sao
1
..,.
S00 29400 aod' ý 250 2eoUo
O 6.0
go10
o
22From the observation, it can be concluded that the landslide was not cause by the triggering rainfall. 'llnc landslide must he somehow due to the antecedent rainfall.
A data of accumulative rainfall had been made to find out the relation of the antecedent rainfall on the landslide and in this study case, the accumulation was taken up to 11 days. Figure 4.3 and 4.4 show the cumulative rainfall at Rumah Nam lk)ta and Ladang Nalla in three months which had highest monthly rainfall record through out the year which are June, July and October.
From the Figure 7, it clearly showed that 23"' October had the highest cumulative antecedent rainfall, 267.0nm, compared to the other days before that. At l. adang Nalla, even the cumulative antecedent raintirll on 23'd October, 243.0mm, was slightly lesser than some other days such as on 29`" July (200.0mm) and on 30`'' July (231. Omm), but the amount was still extremely higher compared to the others. This can conclude that the antecedent rainfall did have a significant influence on the occurrence of the landslide.
Accumulative of 11 -days Ralnfal In Jun* at Rumah Pam Bot.
9ý
II
ýb Z -r 2000 oln o:ý
1s00ýýý
i- -- uun ell n C-1 0 UUUOU 10000ýýýýýOO r- r- "- 11 11 111I 11e- r ri wi : :rNN ýý Tim.. t (day)H
1
- r) WI r- inwoo
it2500
Ii, , /,1000
nnllýllp®ýýo«ýý
mmmmmnn so oý00 '..
ý. ' P1 4) 1 Ob oýýU NNNNOO NAccumulative of 11-days Rainfall in July at Rumah Pam Both 300 0 250 0 200 0 1500 1000 1 500 aaawowaAýýýNNN 00000. - nn 00000®ý0ýýýýOaýý00Dý .,., ý_ ý? u) 1- in N rV (L 1V }ý rl Time. t (day)
Accumulative of 11 -days RainfeN in October at Rumah Pam Bota
2000 , ý 1500 0 c>uoý 100 0 500 000OQ}ý5ýýýpýi ýOdOdýt®®ýiQOý. on ýýhný
0
17 4) ý- 1J1 (y q IQ fY 9 11 ) Time. t (day)F'Ih"urr 4 3. Accumulative ofJ /-days rainfall
. 16r the month u/'(u) June 2(X)7 (h) Ju&
200 7 (c) October 2007 at Kumuh /'um llulu.
w Q0 UU ýrrV aý uýn aý . - ý Y OW) n OO-, .. - ýý 1! )1() H)1i) W)&OnWm ý Cl) ý TN 24
Accumulative of 11-days Rainfall In June, at Ladang Naga U ý- ý ýý P) v) ý 1000 SyVrý0 GNn 60CU00©C) f7Yf H} 50 0 OOOOOOýrýjýIrý1Cýý}ý M1lýf+ýii OOr. ýnot"-"-"-"-"-"-'' n 00 ý"ý_f7DQýýCn_QOaaa rn Y) r- AT . P] Y/ 1 t71 Time. t (day)
i
U ý- op ý., 7ýýýýýýooý_
.. ýýýfiflýýýn, NM
1 ooýý o- V. bOCýp E/ýAIlOOrONýNNfV q4oo ý Cý ýý ui r, ý .i ul :,. ý" ý} yl 1 t7i .. . ry N fV tv N t'1 Timw, t (4oy)Figure 4.4. Accumulative oj'l l -davx rulrf/idl Ji, r the month uJ'(a) June 2IIU7 (h) July 2IX17 (c) October 2007 at l. adanhº Na11a.
ý 250 0
2000
ao o poý o rrr, p NNýNOpp000 n(jnjj r ouý . ý"~ ýc $- 9i°Qý ao II II il 11 "pp °nr'3sle, 4II11111111ri..
nnnn. po
1gý'ýi0V0ýýöýý -1 1 -1 1 fl() ri, cý r. _ ILA A tt a il 111111111111111111111111 11 It 11 11 111111 11 nn ýIflllUýuuuuUUUUUUUUU.U®
Aaob ýý_ ^noULILLIýLIUUUUUUUUUUýY.
W.
Iý9o®a: ýý
00 0) V U) 1- lT .-.. ýN nm.. t (day) }ý 41 i'v ýiAccumulative of 11-days RainfaN in July at Ladang Nalla C. )`, C)C3CJ 300 0
oMro
ý ý, 2500 } e: 'ntlnnn 8 ___ -Iý, or^' H 111111 IID
150 0 1000 50 0 0o fV Huu I i inAccumulative of 11-days Rainfall in October at Ladang Naha
This observation for the slope failure at the hilly area near the Block 13 in t 1"fP suggests that the triggering rainfall or rainfall amount can not he the factor fir this landslide occurrence as the daily rainfall on the day that the landslide was happened was totally very low.
'fhe antecedent rainfall however does give a significant influence on the initiation
of the landslide. In this case. an II -days antecedent rainfall exceeding 2(, A). Qmm appears
to have been sufficient enough to cause a landslide in 11'i'P.
llowcvcr, it should he noted that this conclusion is not the same as other observations obtained from the experiences in other places all over the world. For example, Hrand ct al. (1984) concluded that threshold value ti)r major landslide in Hang Kong as 100mm while according to Rahardjo ct al. (2(()l) in their study case in Singapore, the 90)mm rainfall would be sufficient enough to create a landslide. Ibbcsc differences could be due to the different properties of soils in those particular areas.
However, this conclusion yet might have somc other argument can he made. Sonic people said that the landslide might not be actually occurred on 23' October 2(X)7. ']'he date of the landslide occurrence which was obtained from the Property Management and Maintenance Department of t)nivcrciti 'I'cknologi I'I fRO)NAS (t)'I'P) might not be accurate. Some people said the landslide was occurred earlier than 23`d October and the
problem only being reported later (and in this came, on 23`d October).
If the statements were true, the exact date o1' the landslide occurrence should he laid on sonic where between 27s to 30'" of July 2(X)7. Hasc on Figure 4.5, most the highest antecedent rainfall with elapsed time of I -day to I Way toll on those dates. 'Ilhus chore arc some possibilities that the landslide might be actually occurred on those date.
Highest Antecedent Rainfall in 2007
300 0 250 0 E 200.0r
C 1500 73 E 100 0 U500
o,
o
Elapsed time (day)
C-- (0 N ý ý ý 0 ö to 11
Figure 4. S. The highest unlrrrdrnb raln/ull with r/ulnrd lime u/ 1-duv, , t-div. S-dav, 7-
day, 9-day and /1-day at Rumah /'um ltuba and Ludwig Nullu through out (! 1'2(X) 7.
I- 0 ý r r c 0 ý 1351 .ý ý ýc Oý v ý0 Ir 1L
Rumah Pam Bota Ladang Nails
ý ?ý ýý vf eh ýR o 9
Chapter 5: Conclusion and Recommendation
In the end of this study, the rescunh on the landslide that occurred near the Block 13 in Univcrciti Ccknologi PETRONAS (ti'll') on 23"c ()Ltober 2(x)7 indicates that the landslide was initiated by antecedent rainlüll. The antecedent rainfall is one of* important factors for the occurrence of the landslide. 7ºtc total of 260mm I I-day antecedent rainfall appears to have been suflicicnt to cause a landslide in this case.
I lowcvcr, in this study, thcrc arc somc imlx)rtant kcys had been missing or takcn fir granted which had leaded the result to be not too accuratc. In order to make this kind of r search more succcssful, those things nccd to be stressed and takcn into lull attention;
" Exact date of the landslide occurrcncc ý This detail nccds to be identified first
before prcxxcding to other steps. This date will be the starting point to start analyzing the rainfall data. Without a certain date, the analyzing process will become harder and more complicated.
" Period of cxaninwtc rainfall data 2-year period of daily rainfall data (at least) is
required to make the research more accurate. With a longer period of data, more analyzed data can he compared so that the result that produced later will be more reliable.
" Rainfall data type The hourly ruinfull data is the most prefIcrithic in order to
conduct this kind of rescarch. With the hourly data, the accuracy of the result will he higher.
References
l3nuxi, F. W. (1984). l. andslidcs in Southcust Asia: a stutc-ut=thc-art rC[x)rt. Procccdings of the 4th International Symposium on Landslides. vol. 1. Canadian (; cotcchnical
Stx: icty, 'foronto. 17 59.
Brand, F. W. (1992). Slope instability in twpical arcas. Proceedings ol'thc 61h International Symposium on Landslides, l; cll, D. I I., (cd. ), Balkcnw, Rotterdam, The Ncthcrlands. pp. 2031 205 1.
Chuttcrjca. K. (1 989). Ohscrvation on the fluvial und slops pnxxsscs in Singapore and thcir impect on the urban cnvironmcnt. ! 'hl) 'I'hcsis. National Univ. of Singapore, Singaporc.
l. umb, 1'. (1975). Slopc Failurcx in l long Kong, Quartcrly Journal of I: nginccring
cicology, B. 31-65.
Murray, L. M. and 01scn, M. T. (1988) C'olluvial Slopcs A Gcotcchnical and Climatic
Study. Pnx:. 2nd lat. ('unf. on (; comccchanics in 'tropical Soils, Singaporc, Vol. 2. pp.
573-579.
Pitts. J. (1985 ). An Invcstigation ut' Slope Stability on the N'i'l Campus, Singaparc, Applicd Rescarch Pnojcct Rcixort-RPI/83. Nanyang'I'cchnological Institute: Singapore; 54.
italu"dju, I I., Li, X. W., 'Coll, 1). (;. und l. cong, l:. C. (2(x)1) Thc I"alcct of Antcccdcnt Rainfall on Slope Stability, (kutcchnicul and (; cologicul Engineering 19: 371-399. Kahardjo, If., Kczaur, K. B. and Leong, E. U. (2(X)8) [-. fleet of'Antcccdcnt Rainfall on Pore-Watet Prv, i urc Distribution Characteristics in Residual Soil Slopes Undcr'1'ropical
Rahurdjo, I I., Rcryur, R. B. and Leong. E. C. (2008) Role of Antcccdcnt Rainf'all in Slope Stability, I'rcxxcdings of thc (; 1: ()TR()NI('A, Kuala Lumpur. Malaysia.
tiubramanya, K. (1994) I: nginccring hydrology Second l: ditiun, '! 'utu Mc[)ruw-11i11 Publishing Company Limitcd, Nrw lklhi, India.
Tun, S. 13.. Tan. S. L., Lim. T. L.. and Yang. K. S. (1987). Lauidslide problems and their control in Singapore. rrocccdings of the 9th Southca3t Asian (; cotcchnical ('unf'crencc. Vol. 1, f ankok, I hailand, pp. 25 36.
Wci, J., I lcng, Y. S., ('how, W. C- and Chong, M. K. (1 (r) I). l. undslidc at l3ukit lintok sports complcx. E'rocccdings of'thc 9th Asian ('ontcrcncc on Soil Mcchunics and
Foundation E: nginccring. vol. 1. Eiulkcmu: Kottcrdam; Bunkok, 'Elmilund. 44S 448.
Appendices
1 ý ýýý ,, d...., O. "... ýt. V I1/0A NR aI MAYA RWHM w 4r i4-M-0- (/1A. 1 1 IAWA VAM /AYUItW. A/lwrrr" . MAyAt "AW
I' a... d . +.... 1
Iri)KUMK. N KUALIT7 40. ru lutuw
Nu rum" .0
M)VAP/t: RMMUTALAN VAtA I
tAlrarawtu+a" . wrý I MIMM)IUlilt%JI/IJAVAtAN il
11
ºIM. AIVAN VAN aAIJVAN tlNttl11 ºMHt\ \IVAJAAN I RN)IIJINaAN
1
w'aAauaý) . 1.." 1 /tIVMM1
NO" Aft- 11 MM1n MONO OSWp op. "
f101*a-10l- 3Jyl
tTwaNr
uU1 T1V. wMArrY* pMDI KilA. NMV'ý CA-00,4% ! +w«. I ilAo . {mIft A10%04 . FVL^'"ftM! 1 Nth Its tstM WM t- Yti 4 IM, *- ý ýs ý sYwl N^h" puts" i. r... -w-n1 lt4ýY ýMYRi 0A. -IN. IRywrl
ý wnrwM tNtA TIJ tA /W IRAM I tY-. * 41%r ^Vbq
I. ri. hilrA t}ýrrnwýIýrý
taý.. ywI oray n... hy ýý
4119 111I+Mf / rttry-('. a. eotwd++ao -,. o. CMw w NnaR. 4. wA w++týa r w. r a. wuh 4, UwnlW wNºalsljl PvrraMea (Mf ), ý... "º., ýn/
r li... ýMwN N Vfº T..,. +r...,.. iwýºýIh. NýlW ýý I4 /ý.. ý.... ý "wN ý "Si Iw- trr R,.... / 11. 4ra" º. w" y.. ý htl" r rr .. ý. r 40. s. +. b+ rýº+i ýrr ämýg. Mei»d it ii J%l I MM .. a s+. Nw Jw . W.. r .. ýý .Y*. fa.. V. Iy nr wi w «j Ar . I. J.. . ra -b... r.. d A. . A.. l.. yw. r ... A rb.. ý.. ý . ý. º. rrw ".. /w.. rrrM. Pls. 14". r bw M. wwd r rt.. I ... 1.. ý A. / . Ai... r ra w.. p 4w A- - w. º. m. A. sh... 1. jMrMY. 1"I1 IA. &"d"p r! Iw M... r. « lt.. r.. w
".. w 4... V1 b .. ws A. .. A.. Mr . vr.. r -A ft- 0. A-. J"Vwb. ~ 1. It,, . w0 M. .. " - r... rw .... r. A. ý .b Aºr. ./". -yu r. "o A*v. br -R rrl A. . -. f.. "/.. dr...
An .r 4vdbr. . YM JIw. A. A.. . M. . r.. .. r. P+. r A.. I. wrº+Ir+ M. . grA. r .V Ar 11 w... w/ r wi . p. A . ppft. r+A.... 0h.
fh.. qpMlY4ww+
ý'
i#ýwr IM+4. n
Appendix !: Eorni 1)1.1 (Application form for acquiring hydrological data for the w 4c of government project, research or academic)
Appcndix 2.1. Table ut'1)aily Rainfall 1)utu at Rumah f>um Both I'M 2(K)7 Day 1 2 3 4 5
e
7e
9 10 11 12 13 14 15 16 17 1a 19 20 21 22 23 24 25 26 2$ 29 30 31 Total Jan 00 00 00 00 00 00 180 00 00 200 00 00 200 145 00 00 00 00 340 00 83 5 00 00 00 00 90 00 00 00 00 00 1990 Feb 00 00 00 00 00 00 00 00 00 00 00 80 545 00 22 0 20 0 105 25 0 150 00 28 5 85 00 105 80 00 00 00 2105 Mar 22 5 00 00 0.0 00 00 90 0.0 00 0.0 0.0 0.0 00 00 0.0 00 00 100 8.0 0.0 250 00 6.0 00 00 00 00 0.0 140 40 0 11.0 1365 Apr 00 00 00 0000
00
00
00
00
00
00
32 0 23 0 00 00 90 0000
00
00
00
20 000
31 0 00 21 0 75 25 5 40 0 85 217 5 May 140 0.0 0.0 0.0 0.0 0.0 0.0 0.0 20 00 00 00 0.0 170 4.5 0.9 00 00 00 0.0 00 0.0 0.0 275 75 52 0 100 0.0 00 00 0.0 1345 Jun 00 0.0 42.0 27.0 00 00 00 00 00 00 00 22 0 00 1130 30 00 00 21 0 0.0 0.0 00 00 00 00 00 00 00 0.0 00 00 228 0 Jul 0.0 0.0 0.0 0.0 00 0.0 195 0.0 0.0 00 00 00 0.0 0.0 12.0 00 00 00 0.0 0.0 28 0 470 0.0 30.0 5.5 103 0 120 31,0 00 00 0.0 288 0 Aug 00 0.0 0.0 00 0.0 00 0.0 0.0 00 0.0 0.000
I00
00
00
105 00 15 0.0 80 35 5 0.0 00 00 00 00 0.0 00 00 100 0.0 666 Up 00 395 35 00 00 00 150 00 25 0.0 00 00 0.0 0.0 00 35 0 00 00 0.0 0.0 00 0.0 00 00 00 00 00 0.0 00 00 965 Oct 00 00 00 00 00 7.0 150 80 00 00 00 22.0 00 00 40.0 50.0 00 260 00 500 00 790 00 150 60 00 61 0 00 00 00 24 0 403 0 Nov DK 00 00 00 00 00 00 00 _ 00 0.0 00 00 00 110 00 00 00 00 105 7.0 00 00 00 00 200 00 00 445 00 00 00 00 00 00 00 00 1120 00 10 170 300 00 200 50 00 00 00 65 00 00 00 00 00 00 00 00 00 00 00 00 00 00 910 1936 32Appcndix 2.2.1'ahlc of Daily Rainfall I)iltil
at Runiah Pam Bola for 2008
Day 1 2 3 4 6 ö 7
e
9 10 11 12 13 14 15 16 17 1e 19 20 21 22 23 24 25 26 27 2d 29 30 31 Total Jan 00 95 00 00 70 00 705 81 0 00 37 5 00 00 00 00 85 00 105 00 00 00 00 00 00 00 00 00 79 0 00 00 00 00 3035 Feb 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 0 00 00 350 200 001100
Mar Apr May 00 00 00 00 00 00 270 210 0.0 00 00 00 350 160 00 00 00 0.0 280 160 00 00 15 00 00 00 00 390 180 00 360 00 00 1100 1000,00 00 200 0.0 250 430 00 00 00 00 00 00 00 00 00 00 05 110 00 40 0.0 0.0 80 00 00 00 75 00 00 00 00 750 00 16.0 175 00 00 405 00 00 00 00 120 00 00 00 00 140 0.0 00 00 00 00 00 250 455 00 4870 2680 630 Jun 5.0 0.0 350 15 0.0 180 00 0.0 00 80 00 00 0.0 00 00 00 0.0 00 0.0 00 00 0.0 00 00 00 00 00 00 52 0 00 119 5 Jul 00 00 500 00 00 00 0.0 0.0 00 00 00 00 00 100.0 17.0 0.0 0.0 00 00 37.0 41 0 0.0 9.5 7.0 0.0 00 0.0 00 00 00 00 2615 Aug 00 0.0 00 00 00 00 00 00 00 0.0 0.0 20 5 00 00 00 00 0.0 153 0 0.0 65 180 00 43 0 130 140 32 5 0.0 0.0 50 00 120 3175 Sop 250 00 00 50.0 0.0 0.0 0.0 _., 25,5 00 52,0 30 00 0.0 50 0.0 0.0 00 00 00 00 00 00 8.0 00 00 45 00 0.0 00 00 173 0 Oct
00
00
00
40 00 00 200 55 00 90.0 35 5 00 250 40 300 80 22.0 90 350 420 47 5 0.0 45 30 0.0 00 00 00 00 00 0.0 3850 Nov Doc 00 00 70 00 00 00 0.0 00 00 155 0.0 00 0.0 00 0.0 00 00 150 380 100 0.0 125 60.0 145 23.0 100 00 505 00 00 53.0 00 0.0 00 00 00 410 00 00 00 0.0 00 00 00 0.0 00 280 500 25.0 00 595 00 00 00 4.0 00 0.0 430 00 00 00 3386 221 0APPrndix 2.3. '1'ahlr of I)ail}" Rainfall Data at Rumah Pam Rota Im 2009
Day
1 2 3 4 5e
7e
910
Jan 00 00 00 00 120 00 00 130 00 001 11 00 12 00 13 00 14 390 16 00 16 17 00 21 0 Is i 00 19 001 20 00 21 00 22 150 23 00 24 1}} 00 25 130 26 001, 27 0028
00
29 001 3000'
31 00' Total 1130 Feb Mar 170 00 00 0000
00
0 .0
Apr I May I Jun I Jul
00 00 00 00 00 00 00
00
00
7000
00
20 0 00 150 00 125 70 50 00 21,0Aug I Sip I Oct 1 Nov
-ýý"
104 5 -. use-. -ý_.. ý,.
Appcrxlix 3.1. l ublc of Daily Rainfall Data at Ladung Nalla ür 2(K)7 Dap Jan
00
2 00 3ý 004
o0
S o0e
00
7 200 " 20 f 00,
10 So 11 I 185 12 ý 00 13 i 20 14 ; 00 16 790 1" 00 17 00 1" 80 19 120 20 160 21 810 22 230 23 00 24 290 26 130 26 00 31 Total 30 00 00 00 00 -0 293 5 Feb Mar 00 460 00 00 00 00 00 00 00 10 00 00 00 00 00 00 00 00 00 00 00 00 0 00 00 80 60 47 0 12 0 00 60 00 10 00 330 00 00 00 40 240 80 00 30 00 60, 100 20, 301 00ý 10 00 00 10 00 00 12 0 0.0 28 0 130 230 1050 1910 Apr May 430 00 00 00 00 00 80 0.0 00 00 00 00 00 00 00 00 00 00 00 140 10 50 00 00 340 180 300 230 00 50 150 00 00 00 0.0 00 00 00 105 160 70 00 70 90 100 00 40 320 50 200 130 190 680 00 100.0 00 00 00 00 0.0 2565 1610 Jun 00 _5_2 0 37.0 45.0 6.0 00 0.0 8.0 00 50.0 12.0 70 42.0 47.0 40 0.0 2.0 40 80 00 70 0.0 0.0 00 00 00 00 0.0 0.0 00 3290 Jul 00 0.0 0.0 70 0.0 00 2.0 50 00 0.0 00 00 00 0.0 00 150 Aug 00 00 0.0 0.0 0.0 00 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Sop Oct 480 00 56.0 0.0 401 0.0lo1
0.0
0010.0007.0
190 110 3.0 3.0 20 5.000
0.0
0.0
0.0
00
ö.
0
370 30.0 13.0 26.0 0.0 0.0 35.0 14.0 25 0 14.0 14 --- 0.0 49.0_ 00 48.0 13.0 00 00 8.0 7,0 0.0 00 29.0 0.0 5.0 00 30.0 70 7.0 00 250 32.0 14.0 00 1.0 7'1.010.01
28019.0_
70 25.0 0.0 29.0 20 0 0.0 1.0 31.0 400 10 70 10 520 00 00 110 11.0 0.0 0.0 0.0 4.0 00 0.0 00 60 00 0.0 0.0 00 0.0 0.0 2980 1160 2440 3600 Nov Doc 00 60 10 0 0000
0.0
0.0
00
30 00 0.0 00 30 100 8.0 4.0 0.0 00 0.0 00 50 140 00 160 60 100 00 140 30 00 00 0.0J 00 snJ 20 0 0.0 10 0 3.0 10 00 00 290 00 00 000.0 00 0.0 00 8.0 00 00 00 00 00 00 00 00 0.0 0.0 0.087.01
11701
35Appcrxlix 3.2. Tablc of Daily Rainfall I)utu at I. udang Nalla for 2(x)8
Day Jan Feb
1 00 00 2 00 00, 3 00 150 4
s
"
9 10 11 12 13 14 1ö 1" 17 1" 19 20 21 22 23 24m
30 31 Total 00 20 00 40 00 _ 180se0
00
t50l1
00 f -0 -0 1 00 ,00
00
00
00
00
00
00
001
00
00
1 00 100
00
00
00 25050
100 50 40 30 00 20 00, 00 00, 00 00 00 00 480 00 00 00, 00 001 200 720 00 00 50 00 2010 1600 Mar 40 100 20 21 0 00 45 0 30 30 22 0 40 30 43 0 58 0 00 00 00 00 00 190 160 00 35 0 280 30 0 140 37 0 41 0 00 00 30 40 4430 Apr 300 180 21 0 12080
300 6000
00
00
180 130 170 00 70 00 10 00 00 70 20 0 00 70 00 40 00 00 0.0 30 00 218 0 May Jun 00 0.0 00 00 00 3.0 00 250 00 50 00 100 00 10.0 00 00 00 140 00 00 00 8.0 00 00 00 00 00 0.0 00 0.0 00 0.0 00 0.0 00 00 190 30 00 2.0 00 00 10 0.0 00 4.0 280 20 40 0.0 10 00 00 00 00 0.0 00 0.0 00 10,0 22.0 750 960 Jul 0.0 2.0 00 40 0 00 00 0.0 20 80 00 180 33 0 580 14.0 13.0 00 00 00 00 00 260 1.0 00 51 0 9.0 00 00 0.0 00 00 0.0 2730 Aug 00 001I 00 0.0 12.0 00 0.0 0.0 20 0.0 0.0 0.0 0.0 00 0.0 0.0 0.0 0.0 00 135.0 30 200 00 21 0 300 30 160 58.0 0.0 00 200 3190 8. p 00 00 1120 30 00 23 0 00 00 60 00 33 0 10 0.0 00 00 00 00 00 00 00 00 00 00 00 0.0 00 00 0.0 00 150 193 0 Oct 120 0.0 00 0.0 190 00 7.0 560 16.0 11.0 21.0 45.0 00 00 11.0 35.0 7.0 27 0 6.0 19.0 21.0 15.0 3.0 3.0 4.000
ö.
o
0.0 0.0 4.0 00 3420 Nov 00 00 00 0.0 00 00 00 0.0 110 0.0 00 00 180 30.0 7.0 32 0 00 78 0 00 34.0 00 37.0 150 5.0 60 30 00 00 00 00 276.0 36Appcndix 3.2, Table (, f I)uily Ituinfüll I)utu at Ladung Nalla I'M 2(K)8 Day , Jan I 50 2i 20 I ý 150 0 4 00 I 6t 30 ý
a
00
7
00
" 00 r 230 1 10 00 rý 11 00 r1
1200
1
1300
ýý 1 14 10 0 1 15 22 0 Is 00 00 1" 420 19 20 2000
21 00 22 22 0 23 ý 00 24 00 25 40 2600
6009
00 30 00 31 '80 Total 1660 Fob 0080
00
00
160xo
so
00
00
00
00
150 00 00 00 00 100 00 150 Mar i Apr 00 00 20 0 00 35 0 35 0 20 50 20 ý -s-.May
(
JunI
Jul I Aug I 8. p l Oct- º^ - ? Q?
