Cave systems in Phong Nha - Ke Bang area

v \^ u Jo u rn al of Science, E arth Scicnccs 28 (2012) 217-229

Cave systems in Phong Nha - Ke Bang area

Nguyen H ieu’’*, Vu Van Phai', Howard Limbert’

^Faculty o f G eography, V N Ư University o f Science, 334 N guyen Trai, H anoi, Vietnam

^British C ave R esearch Association (BCRA) Received 02 October 2012

Revised 30 Octobcr 2012; acccpted 20 Dccembcr 2 0 Ỉ2

A bstract. After 22 years with 13 colỉaborative research expeditions between the Faculty of Geography, VNƯ University o f Science, and the BCRA, many eaves in the great limestone blocks o f Phong Nha Ke Bang have been explored and surveyed with a total length o f 163km. Most of them are river caves, connected together to form three main systems: Phong Nha cave system, Hang Vom system and Nuoc M oc system. Phong Nha cave system starts from Hang Khe Ry - the w orld’s longest river cave, to Hang Thung, En, Tra Anh and finally, Phong N ha cave, with a total length o f 79.1km. Hang Vom system starts from Rue Ca Roong cave and ends with Hang Vom with a total length o f 44.3km. Nuoc Moc system which has a large basin located in the west o f Chay River flowing through caves Vuc Ky, Nuoc Lan and Ha Lau is 14.1km long. Most recently, Son Doong Cave o f the Phong Nha system was discovered and is the w orld’s largest cave passage. Some caves have been developed for tourism activities such as Phong Nha Cave and Paradise Cave more recently. However, tourism activities have a large effect on the caves. Beside the research results o f the cave systems in Phong Nha Ke Bang, this report will provide the following analyses: evaluation o f the impact o f tourist activities and environmental changes in the caves, and propose solutions for the effective management and sustainable developm ent o f this valuable resource.

Keywords: Caves, Phong Nha - Ke Bang, Son Doong.

1. Introduction

Phong N ha-K e Bang, tw o huge lim estone m assifs in Q uang B inh province, are the last large lim estone blocks in the direction from north to south o f V ietnam 's territory. It has a long history o f geological developm ent, and is a convergence o f m any factors and favorable natural ccnditions such as lithology, tectonics, topography, hydrology... to form huge

‘ Corresponding author. Tel: 84-4-38581420.

E-mail: nguycnhicu@hus.cdu.vn

underground cave system s. In particularly, it holds world records such as the Khe Ry cave and Son D oong cave. A fter 22 years w ith 13 expeditions and cave research cooperation between the Faculty o f G eography, V NU U niversity o f Sciences and the B ritish Cave Research A ssociation (B C R A ), great underground cave system s in the lim estone blocks o f Phong N h a-K e B ang have been discovered and surveyed w ith a total length o f

163km. M ost o f caves here are the riv er caves, interconnecting to form three m ain systems:

Phong N ha system , H ang V om system , and 217

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N u o c M oc system. These precious natural resources o f the World, Vietnam and Q uang Binh, can be exploited by using multiple objectives for conservation as well as economic and social development, student development designs for local communities.

2. L im eston e m assif P hong N ha - K e Bang and m ysterious cave system s

2.1. C haracteristics o f lim estone m a s s if P hong N h a - K e B ang a n d large cave p o te n tia l

G eological characteristics

T he geological characteristics o f the Phong N h a - Ke Bang, the diversity o f structure and stratigraphy, is the sum o f the product o f six m a jo r stages o f development in the history o f the Earth's crust in the region: Late Ordovician period - Silurian, Devon - early Carbon, and Carbon - Permian stages; M esozoic period:

Cretaceous;

Cenozoic stage: N eogen and Quaternary.

T hese are the conditions which created the diversity o f the unique landscape o f karst terrain and great underground systems o f caves in the karst block Phong N h a - Ke Bang N ational Park.

P hong N ha-K e Bang also presents geological events dem onstrating the historical d evelopm ent o f lively crust over 500 million years, from the Ordovician to the present.

C o m p lex tectonic activity o f the Earth's crust is the cause o f all o f the formation and fracture o f the geological structure, which is the evolutionary spiral to create a normal geological and geomorphological picture today.

G eological structures and lithological c o m p o s itio n diversity is crucial to the diversity o f topography and geom orphology and also affects the decision network hydrology, ground

water, climate - the physical geography, biodiversity and environmental landscape o f a wild and mysterious land o f nature [1].

Research studies are mainly in the Truong Son structure zone (A E Dovjikov and et al, 1965), which is separated from the Hoanh Son zone by faulting Song Ca - Rao Nay, including Dong Hoi lift blocks and blocks drop Phong N ha - Quy Dat. D ong Hoi lift blocks exposed in the south-east o f the study area were created from the terrigenous rocks o f Ordovician- Silurian age. At the center o f Dong Hoi lift blocks, also granitoids blocks o f the Truong Son basis create com plex structures "dome anticlinal". Slump blocks Phong N ha - Quy Dat are exposed in the central part o f the Truong Son zone and are com posed o f terrigenous rocks, alternating carbonate rock, including Cat Dang formation (D3 cd). The terrigenous sedimentary rocks containing organic litter, silica and silica carbonate o f La Khe formation (C \lk) and carbonate (Bac Son formation - CP bs) covcrs unaccordantly on the Cat Dang formation, also involved in mass loss above Cretaceous sediments ( o f Mu Gia formation - K mg), and Cenozoic sediments.

There are two main fault systems and two secondary fault systems. The two main systems are N W -S E and N E -S W trend and the two secondary systems are o f longitudinal and latitudinal trend.

I

N

400 km

Figure 1. Karst areas o f Vietnam.

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G eom orphological C haracteristics

T he diversity o f geological structure - petrographic com bination w ith the hum id fropical clim ate o f Viefriam has created the diversity o f the landform s w ithin the Phong N ha - K e Bang, including k arst and non-karst landform s. A lthough the central m a ssif in form is class size and less differentiated, but overall, the landscape o f Phong N ha - K e B ang is differentiated in the direction o f decreasing altitude from south to north and from w est to east. T he southernm ost part o f the region IS the m ountain range w ith an average altitude o f 1200 - 1600m and peaks com fortable w avy long sub - parallel in the w est to the east-south­

east.

T his is a collection o f tubs for the lim estone m a ssif in the north. From south to north, the lim estone blocks have a relativ ely uniform height, about 700-900m .

F rom w est to east, lim estone blocks o f the Ke B ang form the w atershed area betw een the eastern and w estern T ruong Son. T he V ietnam - Laos bo rd er areas include top lim estone flooring floors each w ith a heig ht o f 800- 1000m. T here exist som e p eak s o f 1200 - 1600m m ade o f red sandstone ro ck o f M u G ia form ation, in the M u G ia Pass area. F rom w est to east, the low er lim estone te ư a in is 600 - 700m and the eastern edge is m oved dow n in steps to 400-500m and 200-300m . T he 100m re lie f level is form ed by the no n-karst rocks com m on in the eastern part o f the region.

T he non-karst topography distribution aro und lim estone blocks o f P hong N ha - Ke B ang, IS form ed by geom orphological processes on th e terrigenous sedim entary rocks and intrusive rocks, and this is also the basin for w ater supply to karst processes and m aterials (m ud, sand, gravel, cobbles, gravel, etc.) w hich

are deposited in the caves as w ell as the area o f P hong N ha - K e Bang. The m ain w ater sources are abundant from this vast region, and have created m ore favourable conditions for the developm ent o f the biological w orld in particular and caves in the k arst area in general.

K arst landform s are the m ost characteristic feature o f the lim estone blocks Phong N h a - K e Bang. First, they account for m ore than 2/3 o f the heritage region, and this is the largest lim estone m a ssif still relatively intact in V ietnam and continuing through Hin N am no o f Laos, it becom es the largest lim estone m a ssif on the planet. T his lim estone block o f 1000m thickness, is m ainly old lim estone C arbon - Perm ian high-purity, texture blocks or subclass th ick . In th ese c o n d itio n s k a rst e v o lu tio n occurs radically: F rom the period o f m any sm all karst funnel cone karst, as it is the final forni o f the tow er and k arst plain. The lim estone fon natio ns in Phong N h a - K e Bang also have m an y c h a ra c te ristic s o f the lim esto n e s in H a Long Bay, N orthern Son (Lang Son province), H a G iang, Son La and Southern China, B ut the location o f the lim estone in the tectonic regim e, clim ate and relationships w ith the su ư o u n d m g non-karst terrain are n o t the same. At H a L ong Bay, the lim estone blocks are in shallow bays along the continental m argin, rising above the sea as hundreds o f sm all islands. Bac Son, Ha G iang, Son La and C hina in general, lim estone blocks are distributed in the m ountains far from the sea and higher than the su ư o u n d in g non- karst teư ain . P articularly in Phong N ha - Ke Bang the lim estone te ư a in is low er than the suưoundings.

For these reason s the evolution o f karst landfonns in P hong N ha-K e B ang IS not exactly the same as elsew here, although this evolution occurs by the sam e m echanism s; dissolution (both surface w ater and groundw ater) and

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m echanical dam age (due to landslides on the slopes and in caves). D ue to these m echanism s, m any styles and types o f k arst topography have been created both on the surface and deep below.

2.2. C haracteristics o f cave system s in P hong N ha-K e B a n g

a) C ave system s a nd their scale

Some cave system s w ith m any caves in the great lim estone blocks o f P hong N ha Ke Bang have been explored and surveyed w ith a total length o f 163km. M ost o f them are river caves, connected together to form three m ain system s.

Phong N ha cave system , H ang V om system and N uoc M oc system . P hong N ha cave system starts from H ang K he R y - the w o rld ’s longest

river cave (table 1), \o H ang T hung, En, Tra A nh and finally, P hong N ha cave, w ith a total length o f 79.1km . H ang V om system starts from Rue C a R oong cave and ends w ith Hang V om w ith a total length o f 44.3km (fig 3). Nuoc M oc system w hich has a large basin located in the w est o f C hay R iver flow ing through caves Vuc Ky, N uoc Lan and H a Lau IS 14.1km long.

N uoc M ooc system is a large resurgence on the w est ban k o f the C hay River. W e are trying to find caves leading into this system. High level stream sinks at 800m altitude south o f the X uong valley have been explored to over 300m deep. M any other caves w est o f the Chay River m ay lead into this system . The source o f the N uoc M ooc w ater is still unknow n. There IS potential for a very long system south and west o f the C hay River.

Table 1. Longest caves o f Vietnam [2, 3-^11]

C ave N am e P rovince Length Y ear E x p lo ra tio n Hang Khe Rhy Quang Binh 18,920m 1997/1999 British Hang Vom Quang Binh 15,760m 1992/1994/09 British Hang Son Doong Quang Binh 8,573m 2009/10 British

Hang Co Ban Son La 8,500m 1994/1998 British/French/I talian Hang Phong Nha Quang Binh 8.329m 1990/92/2010 British

Nguom Ban San Lang Son 5,416m 2001/2003 British

Nguom Sap Cao Bang 5,379m 1997/1999 British

Hang Toi Quang Binh 5,258m 1990/1992 British

Hang Cha Lo Quang Binh 4 ’483m 2007 British

Hang Duat Quang Binh 3,927m 1994 British

Hang Lanh Quang Binh 3,753m 2001 British

Ban Ngam Cao Bang 3,600m 1995 French/Italian

V ucK y Quang Binh 3,460m 2012 British

Hang Thung Quang Binh 3,351m 1994 British

Nguom Nam Lao Cao Bang 3,360m 2001 British

Ki Lu Cao Bang 3,353m 2003 British

Hang Ca-Be Lang Son 3,342m 1992 British

Nguom Pac Bo Cao Bang 3,248m 1997 British

Hang Over Quang Binh 3,244m 1997 Britis’i

Pac Lung Cao Bang 3,109m 2001 British

Bo Luong Lang Son 3,094m 2003 British

Hang Nuoc H oa Binh 3,075m 2003 British

Bo Nhon Lang Son 3,057m 2003 British

Hang Ken Quang Binh 3.018m 2010 British

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The above characteristics show that for both cave system s the entrance is at the current w ater level o f rivers and stream s. The system s can be seen as the largest scale river caves discovered in Asia so far.

b) Cave levels

Five levels o f cave developm ent have been identified in the Ke Bang M assif. N am ely; 0 m;

20 ± 5 m; 50 ± 10 m; 100 db 10m and 200 ± 50 m [12]. A sixth level at 350-400m was suggested after the 2 0 1 0 expedition.

Level 1 or Om is taken as the m odem stream cave level. This includes all the river caves such as Phong N ha, K he Ry and H ang V om ; Level 2 at 20m includes the dry entrance to N uoc N ut,

passage in H ang O ver and H ang V u Ca Tau;

Level 3 at 50m includes H ang Trail and Hang Tron;

Level 4 at 100m, can be seen in the dry high level cave above Phong N ha, H ang Tien Son, and in H ang G io; Level 5 at 200m is seen in H ang Hai C ua and H ang H oa H uong; The evidence for level 6 at 350-400m now includes more than 10 caves, betw een 500 and 1000m long, follow ing the 2012 expedition. These are large m ainly horizontal caves w ith extensive calcite deposits. In m any cases the cave ends w ith a com plete calcite blockage. C aves at this level include H ang Ho N ui, H ang 1987, Hang Cua N ho and H ang Ho Ky.

Figure 2. Cave systems o f Phong Nha - Ke Bang massifs.

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CJ Types o f caves

In term s o f m orphology, m ost o f the caves are high, w ide, and generally linear. Some caves are fairly com plex plane m aps such as M aze Cave (fig. 3). C ross-section o f passages allow s classification such as phreatic or vadose (the cave is divided by type o f relationship with the regional w ater table) and develops over m any cycles.

P hreatic passages are form ed w hen the cave is beneath the w ater table, and vadose passages by active stream entrenchm ent above the w ater table. There is also undoubtedly paraphreatic developm ent, w ith caves having an air surface

under low flow conditions, w hen drainage is w ithin the capacity o f the system , but reverting to phreatic (w ater-filled) developm ent under conditions o f high flow such as in the wet season w hen very high levels o f rainfall are seen.

M ultiple cycles o f cave developm ent are also reflected in the cave floor level as well as the entrance level o f caves.

In the caves there is extensive distribution o f stalactites, stalagm ites, colum ns, and flow stone, w ith beautiful colors and shapes.

There are also m any unusual form ations such as Phytokarst, C onulites and Strom atolites.

Figure 3. Map o f Maze cave [11].

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The cave floor o f En, K he Ry, Dai Cao, also shows the m echanical distribution o f sedim entary debris such as pebbles, sand and clasts bound by lime cem ent.

The study results show that the caves can be divided into two kinds in the blocks o f Phong Nha - Ke Bang: active caves and fossil caves ( f i 4) [\2, 13]

The active caves are the river caves m entioned above and are the low est level in the caves, and still associated w ith groundw ater (aggressive base level) at present.

The fossil caves are divided into:

- 'I'hc ancient phreatic cave now abandoned by the curent w ater table. In the cave there arc

m any beautiful stalactites in evidence, such as Phong N ha dry cave. These caves are m ainly distributed at a higher level. In som e high level caves traces o f occupation by ancient people (such as bone, anim al teeth, shells, pottery shards, etc.) have been observed.

- The old karstic foot caves are the horizontal caves form ed w hen the foot o f the lim estone blocks w as subm erged in w ater. In the area o f Phong N ha - Ke Bang, in these caves there are alm ost no stalactites. These caves are found at the second level, typically Chay cave (or Xa Phong cave), W ine F actory cave (local nam e o f the cave is unknow n).

Figure 4. Active cave (a) - Son Doong cave;

M ost caves have com plex structures consists o f m any branches, each branch consists o f several passages or cham bers. C hanges in size m ay be seen at different levels o f cave and the caves have a very large range o f passage size from 10 to 40-50m in w idth and 10-20-50- 70 to 80m height ... In each cave, 2 to 4 cave levels w ere observed. T he m o st obvious is the cave survey in Bo T rach district as Toi, Vom, Phong N ha caves.

and fossil cave (b) - Bi Ki cave (by Howard L.).

The low est cave level is the river cave level associated w ith an aggressive base cu ư ent o f the river in the highly active areas. D ue to the ability to remove w ater soluble carbonate and the intensity o f the active underground river large cave fom iation will be at the river level.

M any underground river sand beaches are form ed in the cave (Phong N ha, Toi, K he Ry, H ang En ...) (fig. 5).

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M á■t- %

Figure 5. Sand and gravel beaches in En cave (by N guyen Hieu).

C aves in levels 2, 3 and 4 are th e dry caves, h ig hest disfribution in the 10 - 15m, 40 -5 0m , and 8 0 -100m levels. T h e ex ten siv e calcite deposition has p ro d u ced sp e c ta c u la r caves.

T he large-sized cave, steep cave flo o r and activities o f the satu rated zo ne freq u en tly vary depending on the season.; in m a n y o f the cave creating rapids, the ru sh in g w a te r m akes p assin g som e sectio n s very d ifficu lt, such as the m iddle and upper P h o n g N h a cave.

Som e fairly d eep su m ps th ro u g h tw o cave levels are noted an d research e d in the caves V om and Rue C aroong.

R o o f collapse o ften crea tes larg e rock s, as ob served in dark cave. T h e se b reak d o w n hills m ay be rem oved by d isso lu tio n an d abrasion in tim e. Large p hreatic p assag es w ill sh o w a curved or dom e-like r o o f an d b e fairly w ide.

P assages o f vadose origin w ill b e n arro w er and m o re trench-like.

d) Son D o o n g ca ve -th e W o r ld ’s b ig g est cave Son D oong cav e is fo rm ed b e c a u se o f stream capture alo n g a p re -e x istin g N -S ừ en d in g fault (fig. 2 & 6). T h e cap tu re likely o c c u ư e d due to b reac h in g o f a d iffere n t N E - frending fault th at b lo c k ed w a te r flow until

so m etim e d u rin g the P lio cen e to latest M iocene (2-5 M y). T h e cave to d a y tak es an estim ated p eak an n u al d isch arg e o f 40 0-4 50 m3/s, co n sisten t w ith a d rain ag e area o f 200 km ^ At 80-by-80 m e ters in m o st places, the Son D oong cave b eats o u t th e p re v io u s w orld-record hold er, D eer C av e in th e M alay sian section o f the island o f B o rn eo . D e e r C av e is no less than 91-by-91 m e ters, b u t it is o n ly ab ou t 1.6 kilo m eters long. B y c o n tra st, ex p lo rers w alked 7 k ilo m eters into S on D o o n g cave.

T h e a p p ea ran ce o f th e co llap sed dolines and the alon g w ith v e g e ta tio n ap p ea r in the cave have b ro u g h t th e d iffere n ce o f the Son Doong (fig. 8). C au ses th e a p p ea ran ce o f the hole co llap sed b e c a u se in this p o sitio n the thin lim esto n e cave ceilin g , and im portant in tersectio n co in c id e s w ith th e position o f the fracture.

3. C ave a n d ex p lo ita tio n - co n serv a tio n issues 3.1. C aves o f P h o n g N h a - K e B a n g N ational P a r k a n d th e p o te n tia l scien tific value,

eco n o m ic a n d n a tio n a l s e c u rity

T h e cav e has a v ery special natural en v iro n m en t - lo w lig h t, h ig h hum idity, less

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affected by the elem en ts "o u tsid e" w hich form an endem ic faun a and flo ra and there is also the fascination o f the m y ste ry ‘w ild m a n ’.

M any caves in the reg io n o f P h o n g N h a - Ke Bang have b e e n d isco v ered , and th ey are the im portant n atural reso u rces, co n trib u tin g to the developm ent o f to u rism and econ om ic developm ent. Som e cav es h av e b e e n u sed for tourism , such as P h o n g N h a cave, P arad ise cave and they actu ally a tư a c t m a n y to u rists. P hong N ha - K e B an g is facing a b ig c h allen g e to take tourism d ev elo p m en t to a n e w level, esp ecially after the d isco v ery o f the W o rld 's b ig g e st cav e - Son D o ong - m 2009.

C ave in th e m o u n tain s o f P h o n g N h a - K e Bang te ư a in p la y an im p o rtan t ro le in security

an d defense, as h as b e e n w ell dem onstrated in the w ar ag ain st A m erica.

O ne o f th e d irectio n s for the exploitation and use o f th e cav e is to develop adventure travel. A d v en tu re trav el m ean s not ju st a restful v acatio n o r re g u la r visit, b u t this is fravel for ex citem ent, p h y sical ch alleng e and the ex p erien ce o f rem o ten ess. C om pleting the tour the trav eler w ill feel a sense o f accom plishm ent an d h ap p in ess and h av e m a n y lasting m em ories.

T h e k arst to p o g rap h y , on the surface as deep slot can y o n s, lo fty p eak s, or karst valleys w ith steep sid ew alls and th ick forest is a natural land scap e th a t is sure to brin g ừ avelers the po w erfu l feelin g o f ad v en tu re.

Figure 6. M ap o f Son Doong cave.

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Figure 7. M ap in 3D o f Son Doong cave (source: National Geographic).

Figure 8. Doline 1 (by Nguyen Hieu) and 2 (by Howard

c.)

C u rren t tourism activities o f Phong N ha - Ke B an g have no small im pact on the caves here. T he lighting system in use for a long time have the effect o f drying the form ations w hich no lo ng er appear fresh. A lso there is the pheno m eno n o f m oss and algae grow ing on the stalactites (fig. 9, 10). A lso due to the direct im pact o f visitors there w ill be dam age to the fossil cave (fig. 11) such as im pacting o f sedim ents. Som e o f the lay ou t or irrational

displays in the cave also lose aesthetic and natural appeal and a pristine environm ent.

In addition to the assessm ent o f karst landform s for adventure tourism , it is also necessai7 to study and assess the non-karst landform s areas, because they form the w ater basin, creating favorable conditions and difficulties, not to m ention particular risks in adventure fravel.

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3.2. Recom m endations conser'vation

exploitation a n d

The cave is an im portant com ponent, w ith an independent and intim ate relationship w ith

the natural com ponents o f the karst area to create a unique environm ent o f the karst region.

Therefore, there is a need to m anage the cave environm ent to m aintain the karst areas H eritage o f P hong N ha - K e Bang:

Figure 9. a big fresh stalactite in 1990 (left) (by Howard L.) in Phong Nha cave looks dry and "old" (right) (by Nguyen Hieu) after 20 years o f exploitation for tourism.

Figure 10. Moss growing on the stalactites in the Phong Nha cave in the position lights (by Nguyen Hieu).

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Figure 11. Impact to the cave and inability to restore the fossil cave (Bi Ki cave - a branch in Phong Nha cave) (by Howard L.) M inim ize im pact on the environm ent and

landscape o f tourists: L im it direct im pact on the stalactites, the cave, drilling, and path design not by w ood/cem ent, reduce energy lampenilora.

C reate harm ony and intim acy w ith the landscape o f th e cave: L im it the use o f artificial m aterials, natural shape for the item s, do not use light colored lighting.

Pay attentio n to the safety o f visitors:

M onitoring o f air that affect the health O2, C O2, SO2, H2S, etc., recom m ended num ber o f passengers, m o nito rin g and tim ely w arning o f th e areas o f potential risk rock fall/ collapse.

A im to restore the natural environm ent o f the cave, w e need to p lan "closed" Top perio dically to allow the natural environm ent in the cave to get itse lf back on track, use o f environm ental engineering.

R estaurant operators w ill bring econom ic benefits, but w ithout careful consideration and appropriate m an agem ent w ill do dam age to / loss o f values m any tim es larger. Therefore, b efore d eciding on further developm ent there should be:

- T he overall study, detailed study o f the cave (ửie characteristics o f geology, geomorphology, biodiversity, environm ental catastrophe risk);

- T he developm ent o f m ining p ro jects in caves m ust be re fe ư e d to the judgm ent and advice o f professionals, scientists, as w ell as extensive consultation o f the people and all levels o f m anagem ent,

- A ccess to "sustainable developm ent,

- Pay attention to the benefits / benefit o f the local com m unity.

4. C onclusion

W orld N atural H eritage o f Phong N ha - K e B ang N ational P ark w as developed over a lim estone b lock from D evon later (377 m illion years) and P erm ian (250 m illion years).

Surrounding lim estone blocks developm ent o f non-carbonate terrain, p rovides w ater collection conditions for developm ent o f lim estone caves, and at the sam e tim e increases the biodiversity in the region.

G reat u nderground cave systems in lim estone blocks have been detected and m apped w ith a total length o f 163 kilom eters.

M ost caves here are riv er caves, interconnected system s m ade up o f three m ain cave systems:

V om, P hong N ha, and N uoc M oc systems. T he discovery and m apping o f these m agnificent

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cave system s is the effort o f govem m ent, local people and because o f research cooperation betw een the Faculty o f G eography, V NU U niversity o f Sciences, and the British Cave Research A ssociation - BR CA .

The cave system s o f P hong N ha - K e Bang are a precious natural resource o f the W orld, V ietnam , and the local com m unity. W e can exploit them , using m ultiple objectives for the conservation and socio-econom ic developm ent to improve the livelihoods o f local communities.

The construction o f the developm ent plan for P h o n g N h a - K e B a n g N a tio n a l P a rk to 2025 should be com pleted soon. T his m ust be p a rtic u la rly in te rested in c o n se rv a tio n p la n n in g and prom oting the values o f the Phong N ha - K e Bang national park; including a focused review o f valuable natural areas and proposed protection and controlled exploitation o f tourism developm ent, especially the cave system s; control o f construction projects to av o id the in flu e n ce on th e n a tu ra l h e ritag e in core zone and buffer zone. In addition, the general plan should also establish a convenient location, suitable to attract an investm ent project to build parks, develop eco-tourism , but still preserve the integrity o f the natural heritage; enhance infrasfructure conditions and social infrastructure to m eet operational requirem ents, N ational P ark protection, and

research, im proving the living conditions o f the population and needs o f guests visiting.

R eferen ces

[1] Trần Nghi (Chù biên), 2003. Di sàn thiên nhiên thế giới: Vườn Quôc gia Phong Nha - Kè Bàng, Quảng Bình, Việt Nam. Cục Địa chât và Khoáng sản Việt Nam.

[2] Carrieri G. and Preziosi E., 1997. Cao BangM995. International Caver, No.9, pp. 11-

17.

[3] Vietnam 2009: A joint British and Vietnamese caving expedition. 58 pp.

[4] Vietnam 2007: A joint British and Vietnamese caving expedition. 46 pp.

[5] Vietnam 2006: A joint Bntish and Vietnamese caving expedition. 24 pp.

[6] Vietnam 2005; A joint British and Vietnamese caving expedition. 40 pp.

[7] Vietnam 2003; A joint British and Vietnamese caving expedition. 40 pp.

[8] VictTiam 2001. 24 pp.

[9] Vietnam 1999.35 pp.

[10] Vietnam 1997. 45 pp.

[11] Vietnam 1994. 48 pp.

[12] VŨ Văn Phái, Nguyễn Hiệu, Howard L. (2006).

“Đặc điềm hang động karst khối Phong Nha-Kẻ Bàng”. Tuyển tập báo cáo khoa học Hội nghị Khoa học Địa lý toàn quốc lần thứ II, Hà Nội 2006, tr. 337-345.

[13] Ford D .c. and Williams P.W., 1989. Karsi Geomorphoỉogy and Hydrology. Chapman &

Hall, London, UK, 601 pp.