North East Monsoon Rainfall Induced Landslide Hazard and Nonstructural Preparedness

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1 Vasanthakumary Selvanayagam (1) Nrth East Mnsn Rainfall Induced Landslide Hazard and Nnstructural Preparedness (1) Department f Gegraphy, Eastern University, Chenkalady, Sri Lanka. ( vasa84@gmail.cm) Abstract: This study reveals the scenari f landslide hazards and nn-structural preparedness amng the cmmunity. During the NE mnsn rainfall in 2012, the study area experienced a high level f risk frm landslide ccurrences. Due t the lack f preparedness, peple were nt alert enugh in the pre-disaster stage. Since the study area has been identified as a high risk area, ptential landslides culd be expected in the future as well. Therefre, it is necessary t be prepared fr landslide hazards, in rder t reduce the impacts t minimum level. Keywrds: NE Mnsn Rainfall, Landslide, Impacts, Risk, Preparedness Intrductin Sri Lanka, as a small highland, is facing serius threats frm varius types f natural hazards such as flds, drughts, landslides and extreme weather cnditins due t its different types f physical features. Amng them, the landslide is ne f the very cmmn natural hazards in the cuntry. Sri Lanka has been experiencing a spate f landslides ver extensive areas f the central hill cuntry and suth western regin since the early eighties (Amaratunga, 1994). Wrld Atlas f Natural Hazards als states that, landslides are the mst frequent and widespread natural hazard n Earth (Jelinek. R, et, al, 2007). The term Landslide is restricted t mvement f rck and sil in the brad range f velcities even slw mvements which are rarely a direct hazard t life can destry buildings r break buried utility lines (Kularathna, 1998). Sme landslides mve slwly and cause damage gradually; whereas thers mve s rapidly that they can destry prperties and take lives unexpectedly. The threats which caused by landslide events in Sri Lanka are cnsidered t have significant negative cnsequences n varius sectrs which are highly depending n envirnmental cnditins. In general, landslides are assciated with the perids f heavy rainfall. Histry f Landslide events in Sri Lanka clearly indicates that cntinuus and intensive rainfall has triggered a number f catastrphic landslide events in the hill cuntry regin. This tendency has attested by mst f the Sri Lankan researchers with appsite verificatin. Nrth-East mnsn, which is ne f the predminant climatic seasns in Sri Lanka, having variability in rainfall, brings extreme weather cnditins t Sri Lanka in the recent past. Accrdingly, during the recent Nrth-East mnsn rainy seasn in Sri Lanka which started in the mnth f December 2012 aggravate the situatin f the cuntry by causing a significant number f natural hazards such as landslides and fld events. Thse negative situatins were caused nt nly prfund harm t the lives and prperties but als severe decrease in ecnmy and scial develpment f the cuntry. This status clearly indicates that the impacts f landslide hazards drive the peple int high risk and sciecnmic structure f the peple is becming wrse. Thus, it is necessary t take apprpriate remedial actins t avid the impacts f landslide hazards. The peple wh are living in landslide prne areas shuld be guarded frm the lsses f lives and prperties. In general, lack f mitigatin and preparedness measures cause high level f impacts, besides mitigate r prevent the landslides will nt be pssible always. Hwever, by implementing prper [87]

2 Prceedings f the Third Internatinal Sympsium, SEUSL: 6-7 July 2013, Oluvil, Sri Lanka preparedness measures, the impacts f landslide hazards can be reduced. Thugh, the landslide events usually ccur with a shrt ntice, it can be predicted. Because f that, preparedness phase is becming as a mst imprtant part in the disaster management. Preparedness is shrtly defines as planning hw t respnd t a hazard. This phase invlves tw main parts which are structural preparedness measures and nn structural preparedness measures. Preparedness measures include preparedness plans; training; warning systems; cmmunicatin system; evacuatin plans and training; resurce inventries; and public infrmatin /educatin (Internatinal Strategy fr Disaster Reductin (ISDR), 2012). Part f this preparedness depends n hw the cmmunity has the knwledge and hw they respnd t landslide hazards (Iyengar, 1998). Accrdingly, this research addresses an imprtant prblem in the pre-disaster stage and particularly discusses the nn-structural preparedness twards landslide hazards. Backgrund f the Prblem The Matale District situated abve 2147 feet frm Mean Sea Level (MSL) experiences a number f landslides and subsequent flds due t the intensive rainfall in this perid. Several areas in the Matale district were affected by landslide ccurrences caused a number f deaths, displacement and damages t the prperties. Amng them Rattta is a key area which faced severe negative circumstances due t landslide hazards. Eight deaths were reprted and 3,242 persns belnging t 1,029 families were displaced. They have been accmmdated in 14 temprary shelters. The Ministry f Disaster Management has allcated ver Rs.2.5 millin additinal funds fr disaster relief in the Matale district. These recrds shwed that, the peple living in landslide prne areas f Rattta had a vulnerable situatin frm landslide hazards which were triggered by last Nrth-East mnsn rainfall. On the ther hand, these catastrphic events have caused huge impacts n the ecnmy and scial structure f the peple in this district. Thrugh the investigatin carried ut in landslide prne areas especially in Ukuwela, Rattta and Naula, it has been ascertained that 127 areas in 29 GN Divisins have a high risk f landslide events in Matale District (NBRO, 2012). Mst f them are belnging t the Rattta DS Divisin. Bdhiktuwa, Alaklamada, Punchiselvakande, Kandenuwra West, Kandenuwara East, Madakumbura, Dhambaglla, Hungrankandha, Velangahawatta, Bambarakiriyella are sme areas that have been identified as high and mderate risk area fr landslide hazards. Out f them, Punchiselvakande and Kandenuwara East have been selected fr this particular study t analyze the scenari f landslide hazards and nn-structural preparedness level twards the landslide hazards. Accrdingly, the research questin f this study is, hw the peple were affected by NE mnsn rainfall induced landslide hazards in December 2012 and hw much they are ready t face the landslide hazards t be ccurred in future. The bjectives f this research are t understand the scenari f Nrth-East mnsn rainfall induced landslide hazard, identify the impacts and t assess the level f nn-structural safety and preparedness measures twards the landslide hazards. Materials and Methds Since the study primarily fcusing n the scenari f landslide hazards and the preparedness level, disaster management theries were applied t this study. Out f the majr phases f the disaster management cycle, cnsiderable pririty has been given t the phase f risk reductin t analyze the preparedness level. While identifying the scenari, these study mainly emphases n nn-structural measures like awareness, knwledge and practices amng the cmmunity. Thugh, the study deals with bth primary and secndary data, primary data were the fundamental data surce f this study. These data were cllected thrugh key infrmant interview, fcus grup discussins and questinnaire survey. Amng them, a questinnaire survey was ccupied as key primary data cllectin methd fr acquiring infrmatin n the experience f affected peple and the preparedness level twards the landslide hazards. Apart frm this, grup discussins were carried ut with the cmmunity t identify the general picture f [88]

In additin, secndary data were als accmmdated t understand the nature f prblem, impacts, affected families and prvided reliefs t thse families.

3 Vasanthakumary Selvanayagam Nrth-East Mnsn Rainfall Induced Landslide Hazard and Nnstructural Preparedness the preparedness. Key infrmant interviews were cnducted with a scial develpment fficer and rural develpment fficer f the Rattta DS divisin. In additin, secndary data were als accmmdated t understand the nature f prblem, impacts, affected families and prvided reliefs t thse families. 30 families were selected frm the affected families thrugh purpsive sampling techniques fr the survey. Cllected data were analyzed thrugh quantitative and qualitative analysis methds. Ranking and descriptive methds specifically used t analyze the qualitative data. This qualitative analysis part identifies why these cmmunities are having prblems and hw they are ging t face frthcming landslides. Study Area The study area is situated in the suthern part f the Matale district in Central Prvince f Sri Lanka. The ttal land extent f the study area is abut 478ha. The study area experiences frequent rainfall almst thrughut the year. Since the study area belngs t Upcuntry Intermediate Zne, it receives annual rainfall f abut 110 inches during bth suthwest and Nrtheast Mnsns. The average temperature is abut 18 0 C. Bth Punchiselvakande and Kandenuwara East are tea estates; majrity f the peple wh lives in these estates are wrking as estate labrs with lw incme. Each f these areas has specific and different ecnmic and sci cultural characteristics. The wrkfrce cmprises f 266 wrkers, wh are n daily paid. Lcatin map f the study area is shwn in figure 01. The study area is als shwn in landslide hazard map f Matale district prepared by the Natinal Building Research Organizatin. Figure 1: Map f Landslide Hazard Znes and Lca n map f the Study Area Surce: Natinal Building Research Organizatin (NBRO) Surce: Prepared by Researcher, 2013 rainy seasn is a cmmn phenmenn in this area. It differs frm smaller scale earth slide t larger scale rck falls. It is imprtant t nte the histry f landslide hazards where there was a huge landslide ccurred in the study area in 1983 causing 13 casualties and severe damages t lives and prperties. Figure 2: 3D Map the Study Area Results and Discussin The study revealed that the study area has been experiencing a significant number f small and large scale landslide hazards and identified as a high risk area fr landslide hazard by the Natinal Building Research Organizatin. Figure 02 shws the 3D map f the study area and it indicates that, the eastern part cnsists f the higher elevatin f mre than 1000m. Nrthern and western parts cnsist f valleys and lwlying areas. Occurrence f the slpe failures in the Althugh, smaller scale slpe failures typically ccur alng the rads and the slpes in this area, during December 2012 Nrth-East rainfall aggravate the disastrus situatin. The natural factrs f study area such as tpgraphy, gelgy, slpe types, sil structure and tributaries are mechanically leading t high ptential landslide hazards. Hwever, intensive and cntinues rainfall is the majr triggering factr fr several landslide ccurrences which were experienced during last nrtheast mnsn seasn. [89]

Prceedings f the Third Internatinal Sympsium, SEUSL: 6-7 July 2013, Oluvil, Sri Lanka Figure 03 shws the average annual rainfall statistics f the study area frm 1999 t 2012.

4 Prceedings f the Third Internatinal Sympsium, SEUSL: 6-7 July 2013, Oluvil, Sri Lanka Figure 03 shws the average annual rainfall statistics f the study area frm 1999 t During this perid, the mnth f December has received mre than 600 mm rainfall in bth 2006 and This shrt term high intense rainfall in 2012 has direct relatinship with ccurrence f landslide hazards in the several parts f the study area. As per the glbal trend, there is ging t be a particular increase in rainfall intensity in Sri Lanka. Recently antecedent rainfalls and shrt term high intense rainfalls have becme a general weather cnditin in the cuntry (Rathnaweera, et, al, 2012). During the last ten years it has becme evident that mst devastating landslide events tend t ccur as a result f cmparatively shrt duratin, high intense rainfall cmpared t the previusly had lwer intense prlnged rainfalls in Sri Lanka (Ibid). This will lead t the ptential landslide hazards as increasing trend. Figure 3: December Rainfall Trend in Study Area landslide hazards. Amng them 33 huses have been identified in high risk areas in Kandenuwara East and Punchiselvakande GN divisins and it have been pinted ut in table 01. These statistics are clearly ntified that, the landslide hazards will becme a serius issue and the severity f the prblem will be leading t high vulnerability in the future. This Disastrus situatin caused significant impacts t the cmmunity. During the phase f landslide hazard, the cmmunity was helpless. Intense rainfall blcked the transprtatin by causing rck slides alng the rads f the study area, and it caused cmplicated situatin t the fficers f lcal authrities t guard the peple frm hazardus situatins. Hwever, next t the clearance f the blcked rads, they culd manage t reach the affected areas and direct the peple fr the safeguard. Subsequently, peple were asked t mve t the nearby schl by lcal authrities and they were accmmdated in Figure 4: Land use map f the Study Area Surce: Reprts f Pitakande Estate and Meterlgical Department Data Apart frm natural factrs, anthrpgenic factrs als cntribute t the landslide ccurrences in this area. Mre than 85% f the land area is utilized fr cultivatin, particularly tea. The slpe areas f the muntainus regin have been entirely changed by human interventins. Figure 04 illustrates the land use pattern f this area. In additin t agricultural activities, clearance f land and cnstructin f the huses n the slpe areas are fremst factrs which are influencing n the slpe failures. Due t this hazardus situatin, a significant number f huses have been identified as high and mderate risk fr Surce: Prepared by Researcher, 2013 Pitakande Maha Vidyalayam. Thse affected peple faced lts f challenges when they were asked t displace. Even as rank the impacts f landslide hazards based n the pririties, lss f lives (tw children) cmes first. Next t that, lss f huses, displacement, fractures and cracks in the huses, lss f livestck, are sme imprtant impacts arused due t this hazard. [90]

Vasanthakumary Selvanayagam Nrth-East Mnsn Rainfall Induced Landslide Hazard and Nnstructural Preparedness Divisin Table 1: Number f Huses iden fied in Landslide Risk Areas Kandenuwara East

5 Vasanthakumary Selvanayagam Nrth-East Mnsn Rainfall Induced Landslide Hazard and Nnstructural Preparedness Divisin Table 1: Number f Huses iden fied in Landslide Risk Areas Kandenuwara East Punchiselvakande Land Extent (ha) High Risk Mderate Risk landslides is relatively better amng the cmmunity. Hwever, sme peple in the study area are unaware f the past landslides and landslide prcesses prevalent in this area. Meanwhile the cmmunity s awareness f the signs f the landslide was relatively lw in predisaster stage. Figure 5: Knwledge n Past Landslide in the Study Area Ttal Apart frm the primary impacts, secndary impacts als significantly affected the cmmunity. Amng them the impacts which were arising frm the camp (schl) enduring still. Secndary impacts such as lss f incme, emplyment, shrtage f fd and drinking water, impacts n educatin f the schl children, difficulties arise frm camps such as cnflicts, disturbance, privacy related issues, psychlgical prblems, and dependency are vital. Next t the incident three weeks later, mst f the families were relcated in their wn huses again; still, twenty ne families were accmmdated in the schl with the expectatin f alternative huses. Qualitative analysis f the satisfactin level f reliefs prvided indicates that 27% f the cmmunity were satisfied with the relief while 67% with mderate satisfactin. The peple wh were nt satisfied with the relief were very lw (6%). This percentage shws that, the majrity f the cmmunity peple were with mderate satisfactin and cnsiderable assistance has been prvided t the cmmunity. Even thugh the lcal authrities and ther institutins endwed with reliefs t reslve the existing needs f the peple, their prblems are still lasting as unslved. The rle f nn-structural preparedness level f this cmmunity is the mst imprtant factr which determining the impacts. Surce: Field study, 2012/13 Thugh, study area undergne landslide prblems in the past, peple were unaware f the symptms f the landslide. After the ccurrence f landslide in December 2012, the cmmunity culd be able t identify the warning signs. The main signs identified by the cmmunity were, frmatin f fractures, sliding f sil and rck, increase in water level, the frmatin f water surce, turbidity f water, and frmatin f mud water thrugh fractures. Discussin with the cmmunity clearly indicates that they are aware f signs after the landslide event via virtual experience. Table 02 shws the difference between the awareness f the symptms f landslide hazards in pre and pst disaster phases. Table 2: Signs f the Landslide Hazards iden fied by the cmmunity The study reveals that the cmmunity s awareness, knwledge and practices twards landslide are nt in a satisfactry level due t their sciecnmic cnditins. This level is identified by means f knwledge n past landslide, symptms and causes f landslide hazards and mitigatin measures. Results revealed that the knwledge n the past Categry Belw than tw ( 2) Between three t fur (3-4) Mre than five ( 5) Surce: Field study, 2012/13 Pre-disaster stage 72.6% 26.4% - Pst-disaster stage 36.3% 39.6% 23.1% [91]

6 Prceedings f the Third Internatinal Sympsium, SEUSL: 6-7 July 2013, Oluvil, Sri Lanka Similarly, the cmmunity was nt cnscius with the factrs respnsible fr landslide hazards in this particular area. The majrity f the cmmunity, pinted ut that, rainfall is the main triggering factr f slpe failures, but they were unaware f human factrs which are respnsible fr that. This implies that, they cmpletely deem that human interventin n the slpes will nt trigger the landslides. This can be demnstrated thrugh the several imprper human interventins which already incrprated n the slpes. Fr an example, huses have been cnstructed n the steep slpe area which already undergne landslide prblem withut the apprval frm the relevant authrities. Even thugh, relevant authrities instructed the peple t avid the cnstructins, activities were taken place due t several necessities f the cmmunity. Due t the lw level f awareness f the cmmunity n the precise causes and the warning signs f landslide hazards, the steps t be taken during the perids f heavy rainfall were nt taking place. Even after the identificatin f the signs, they didn t take immediate actin t mve t safer places due t the ignrance and dispassin. While cntinuing the intense rainfall and NBRO s landslide warning; the peple were staying at their huse; even after they accmmdated in camps, sme f the peple in particular, males having the practice t g their huses t sleep at night and they back t the camps next day. This kind f dispassin happened due t the imprper guidance and awareness. Being a cmmunity with a very pr educatinal backgrund, they face lt f challenges t understand the instructins given by the authrities, such as understanding and language prblems etc. Hwever, it culd be nticed that, yunger generatin, in particular schl children; have cnsiderable knwledge f the signs and causes, mitigatin measures than the elder peple t a certain extent. due t their traditinal ccupatin. As mentined earlier, thugh, the reliefs have been prvided sn after the incident, awareness prgrams were nt cnducted in this cmmunity. Apart frm abve mentined nn-structural preparedness measures, structural measures als inadequately practiced in this area. With the prper slpe management measures mst f the slpe failures which ccur in this area can be mitigated. Hwever, nne f such practices were implemented yet, besides, such structural practices require advanced technical apprach and als it is very expensive. Cnclusin and Recmmendatins December 2012 rainfall induced landslide event which caused a number f negative impacts t the cmmunity and there are ptential landslides can be expected in the future as well. Thugh the gvernment has taken several steps t imprve the existing mitigatin and preparedness level; impacts f the landslide hazards have nt reduced yet in the study area. Particularly, the Natinal Building Research Organizatin has undertaken a number f prgrams t reduce the risk. Hwever the devastatin f the last event ccurred in December 2012 reminds that landslide prblem has nt reslved yet. Therefre the cmmunity has t be prepared t reduce the high level f vulnerability. If prper attentin is given by the relevant authrities cnsidering the ecnmic cnditin, educatinal level and language f the cmmunity, impacts f landslide hazards culd have been minimized. Therefre, the study clearly enlightens that vulnerable cmmunity has less awareness and hence need mre attentin twards mre fcused preparedness prgrams. The fllwing recmmendatins will supprt t reduce the impacts and imprve the preparedness level f the cmmunity. This cmmunity believes that; the landslide is an unavidable hazard and it cannt be mitigated; mving t the landslide free znes is the best slutin t get prtectin; but, they have n chice f alternative lands, huses and livelihd. Als majrity f the peple were nt interested t mve t a different place Develp the sustainable slpe management practices in the high slpe area and implement different types f landslide hazard risk reductin measures fr different parts f the slps [92]

7 Minimize the human interventin n the hill slp regin thrugh stringent legislatin r by apprpriate awareness prgrams, particularly, cnstructin f huses in the steep slpe area shuld be avided Prvide prper trainings t build the knwledge and undertake necessary actins t avid imprper human interventins n slps. Prvide alternative lands and livelihd facilities in secure places accrding t their preference Strengthen the skills f the cmmunity thrugh apprpriate and sufficient awareness prgram twards risk reductin The cmmunity shuld aware f their vicinity, landslide prcesses prevalent in the area and ptential sites fr landslide hazards Educate the public n the causes, symptms and the mitigatin measure f the landslides and peple shuld be trained t recgnize immediate actins t be taken sn after the identificatin f the symptms f landslide hazards, particularly, during the rainy seasn Mre fcused awareness prgrams shuld be implemented based n the sci-cultural characteristics f the cmmunity Vasanthakumary Selvanayagam Nrth-East Mnsn Rainfall Induced Landslide Hazard and Nnstructural Preparedness References Dahanayake, K., (2009) Appraches fr Landslides Disaster Risk Reductin and Making Cmmunities Resilient Natinal Sympsium n Creating Disaster Free Safer Envirnment, NBRP & Ministry f Disaster Management & Human Rights : Clmb. Hemachandra, D.,(2009) Cmmunity Based Strategies fr Management f Landslide Disasters A case study n Napititenna Village in Nuwara Eliya District Natinal Sympsium n Creating Disaster Free Safer Envirnment, NBRP & Ministry f Disaster Management & Human Rights : Clmb. Gunathilaka, P., (1994) Prblem f Husing and Settlements in Disaster Prne areas with particular reference t landslides Natinal Building Research Organizatin, Sri Lanka: Clmb. Katuptha, K.N.J., (1998). Sci Ecnmic aspects f Disasters related victims and vulnerable cmmunities Prceedings f the wrkshp n Rle f Research & Develpment Institutins in Natural Disaster Management, Centre fr Husing Planning & Building, Sri Lanka: Clmb. Kulatunga, A.A & Sapuktana, U., (1998). Impact f Natinal and Sectral Plicies n Landslides Sri Lanka Prceedings f the wrkshp n Rle f Research & Develpment Institutins in Natural Disaster Management, Centre fr Husing Planning & Building, Sri Lanka: Clmb. Rathnaweera, T. D., Palihawadana, M. P., Rangana, H. L. L, and Nawagamuwa, U. P., (2012), Effects f climate change n landslide frequencies in landslide prne districts in Sri Lanka; Overview Civil Engineering Research Exchange Sympsium 2012, Faculty f Engineering University f Ruhuna: Sri Lanka. [93]

UN Committee of Experts on Environmental Accounting New York, June Peter Cosier Wentworth Group of Concerned Scientists.

UN Committee of Experts on Environmental Accounting New York, June Peter Cosier Wentworth Group of Concerned Scientists. UN Cmmittee f Experts n Envirnmental Accunting New Yrk, June 2011 Peter Csier Wentwrth Grup f Cncerned Scientists Speaking Ntes Peter Csier: Directr f the Wentwrth Grup Cncerned Scientists based in Sydney,