A Geographic Information System (GIS) for environmental management of the Mombasa coast, Kenya.

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2 BRITISH GEOLOGICAL SURVEY TECHNICAL REPORT WC/96/4 1 Ovrss Gology Sris A Gogrphic Informtion Systm (GIS) for nvironmntl mngmnt of th Mombs cost, Kny. T M Willims, A C Mcknzi & J G Rs British Gologicl Survy, Kyworth, Nottinghm, UK. A rport prprd for th Ovrss Dvlopmnt Administrtion, Nturl Rsourcs Division, Environmnt Rsrch Progrmm (ERP) undr ODA- BGS contrct R6191: Lnd-Ocn Contmintion Study (LOCS). ODA clssifiction - b... Subsctor: Environmnt Rsrch Progrmm Projct titl: Lnd-Ocn Contmintion Study (LOCS). Projct Rfrnc: R Bibliogrphic rfrnc: T M Willims, A C Mcknzi nd J G Rs. A Gogrphic Informtion Systm for nvironmntl mngmnt of th Mombs cost, Kny. Ky words: Gogrphic Informtion Systm (GIS), Intgrtd Costl-Zon Mngmnt (TCZM), pollution, mtls, hydrocrbons, orgnochlorins, sdimnts, wtr, suspndd prticults. Covr illustrtion: Mombs Hrbour, viwd from th Kny Mrin nd Fishris Rsrch Lbortory, Nyli.

3 1: SUMMARY A gogrphic informtion systm (GIS) for us in nvironmntl plnning nd intgrtd costlzon mngmnt (ICZM) of th Mombs cost, Kny, hs bn dvlopd s componnt of th Est Africn phs of th UK Ovrss Dvlopmnt Administrtion (ODA) Lnd-Ocn Contmintion Study (LOCS). Th ODA-LOCS dtbs holds informtion on rng of gochmicl prmtrs (including mtls, ptrolum hydrocrbons nd orgnochlorins) for inshor nd nrshor sdimnts, suspndd prticult mttr nd wtr, plus ocnogrphic nd sdimntologicl informtion of rlvnc to th ssssmnt of contminnt trnsport. It s structur dhrs to tht of pr-xisting dtbs for th ntir costl rgion of Kny, compild by th Unitd Ntions Environmnt Progrmm (UNEP) undr sub-progrmm EM16 of th Action Pln for th Protction, Mngmnt nd Dvlopmnt of th Mrin nd Costl Environmnt of th Est Africn Rgion. Whn usd in conjunction, th ODA-LOCS nd EAF/6 dtsts provid powrful tool for idntifying rs of potntil conflict btwn contminnt dischrgs or disprsl plums nd nturl rsourc utilistion within th costl zon of Mombs. This cpbility my b of vlu to plnnrs in optimising th siting of dischrg piplins, nd in th dlintion of non-impctd wtrs for ctivitis such s rtisnl fishing, qucultur nd rcrtion. 2: INTRODUCTION: In 1995, costl-zon pollution monitoring progrmm for dvloping countris, th Lnd- Ocn Contmintion Study (LOCS), ws inititd by th British Gologicl Survy (BGS) undr funding from th UK Ovrss Dvlopmnt Administrtion (ODA) Nturl Rsourcs Division (NRD). Th cntrl objctivs of LOCS r (i) th provision of dt rgrding th sourcs, trnsport pthwys nd fts of contminnt mtls nd slctd orgnic compounds long urbnisd costl mrgins, nd (ii) promotion of th us of such dt in intgrtd costl-zon mngmnt (ICZM). A systmtic gochmicl nd hydrochmicl survy of th inshor wtrs of Mombs, Kny ws crrid out undr th ODA-LOCS progrmm in liison with th Kny Mrin nd Fishris Rsrch Institut (KMFRI) during th priod Sptmbr 1995 to Fbrury (Willims t l., 1996; Rs t l., 1996). Th survy includd ssssmnts of hvy mtl, hydrocrbon nd orgnochlorin concntrtions in wtr, suspndd prticult mttr (SPM) nd sdimnt in ll inlnd lgoons nd th rf-fringd nrshor nvironmnt xtnding northwrd from Mombs Islnd to Mtwp. Ocnogrphic nd sdimntologicl dt of rlvnc to th intrprttion of contminnt distributions nd trnsport pthwys wr lso collctd. All dt r hld in rltionlly-linkd fils, ccssd using th GIS pckg ARCVIEW. During th priod , n lbort GIS holding informtion on lnd-us, industril, rcrtionl nd fishris ctivitis throughout th costl rgion of Kny ws dvlopd undr subprojct EAF/6 of th Unitd Ntions Environmnt Progrmm (UNEP) Action Pln for th Protction, Mngmnt nd Dvlopmnt of th Mrin nd Costl Environmnt of th Estrn Africn Rgion. Th Action Pln is coordintd by th UNEP Ocns nd Costl Ars Progrmm Activity Cntr (OCA/PAC), Nirobi, nd ims to provid rgionl-scl pproch to costl nd mrin pollution-control in th wtrs of nin ffiitd stts (Kny, Mozmbiqu, Comoros, Runion, Mdgscr, Muritius, Sychlls, Somli nd Tnzni). Mngmnt of th EAF/6 Kny dtbs hs, sinc 1995, bn dlgtd to KMFRI. No dtild gochmicl or mrin pollution dt for th inshor wtrs of Mombs r currntly hld on this systm. Th intgrtion of th ODA-LOCS nd EAF/6 dtbss within singl GIS offrs th potntil for crting powrful tool for us in futur ICZM nd nvironmntl plnning for th Mombs r. Such systm would, for xmpl, prmit th vlution of go-rgistrd pollution dt in conjunction with sptil informtion on commrcil or rtisnl fishing ctivity, rcrtionl wtr us or rs prioritisd for mrin consrvtion. Th pproch would llow rs of dirct conflict to b idntifid, nd scrc pollution control rsourcs to b focusd into rs of grtst urgncy. This rport summriss th scop nd cpbilitis of n intgrtd GIS for Mombs, incorporting both EAF/6 dtfils nd nw ODA-LOCS pollution dt, rcntly dvlopd by BGS. It is nticiptd tht ll informtion compild will ultimtly b downlodd to th EM16 dtbs t KMFRI. It rquirs mphsis tht this

4 documnt is usr mnul, nor n intrprtd ccount of th gochmicl, sdimntologicl nd ocnogrphic dt hld within th systm. (dtils of ths spcts of th ODA LOCS projct r providd in two indpndnt tchnicl rports:- Willims t l., 1996; Rs t l., 1996). Th im is simply to outlin th scop of th dtsts now vilbl, nd thir possibl utility in ICZM. 3: SOFTWARE FOR PROCESSING ODA-LOCS DATA. Th commrcil GIS pckg ARCVIEW hs bn doptd s th cnul tool for th compiltion nd nlysis of ODA-LOCS dt for Mombs. Th pckg is rpidly ttining th sttus of n industril stndrd, th us of which hs fcilittd th dirct intrchng of rw dtfls nd procssd multi-componnt 'viws' btwn th ODA-LOCS GIS nd EAF/6 dtbs (which utiliss th sm softwr). ARCVIEW cn b run on modst work-sttion hrdwr. Bsic oprting rquirmnts r n IBM or 1% comptibl PC (386 or ltr), MS- DOS (vrsion 5. or ltr), MS Windows (vrsion 3.1 or ltr), 8 MB of vilbl mmory nd 12 MB of swp spc. Th systm fcilitts th disply, visulistion, nd intrrogtion of go-rgistrd dt, ithr s individul thms or s sris of simultnously projctd lyrs. Although dsignd primrily s usr-fnndly front-nd for ARC-INFO, ARCVIEW cn lso rciv input fils from othr sourcs. Dt procssing cpbilitis includ summry sttisticl nlysis, dlintion of gogrphic rs on th bsis of spcifid ttributs or ttribut combintions, nd th intgrtd prsnttion of mps, chrts nd rltd grphics. Export fils cn b utilisd by wid rng of softwr pplictions such s MAP-INFO. 4: REGIONAL-SCALE DATASETS. Go-rgistrd dt rlting to ovr 8 humn nd nvironmntl vribls within th costl rgion of Kny r hld on th UNEP EAF/6 dtbs. Approximtly 3 of ths thms, with prticulr rlvnc to th objctivs of th ODA LOCS projct, hv bn downlodd to th ODA-LOCS dtbs, providing rgionl-scl frmwork for th prsnttion nd intrprttion of LOCS pollution dt. Th trnsfrrd dtsts dpict costl lnd us, industril ctivity, towns nd sttlmnts, wst disposl sits, rivrs, intrfluvs, costl nvironmnts, rs prviously impctd by oil pollution, port infrstructur, mrin prks, offshor bthymtry, slinity, tmprtur, plgic fishris, sport fishris, rtisnl fishris nd shllfish bds. Th covrg providd by ths fils is nonuniform but typiclly xtnds to th Somli bordr in th north, th Tnznin bordr in th south, nd th town of Voi t 38.5" wst. A rgionl 'viw' or multi-thm img gnrtd through th simultnous rtrivl of thr importd EAFI6 fils (towns, mrin ntionl prks nd offshor bthymuy) is shown in Figur 1. 5: LOCS DATA FOR THE 'MOMBASA WINDOW'. Th sptil covrg of th ODA-LOCS survy is confind to polygon or window ncompssing th dministrtiv district of Mombs nd it's ssocitd inshor nd nr-shor wtrs. Th prcis r of covrg is 3.95' "s nd 39.5" - 4"E. Dt importd from th EAF/6 dtbs cn b rtrivd nd displyd spcificlly within th dimnsions of this window s xmplifid in Figur 2, thus simplifying th simultnous projction of LOCS nd EAF/6 dt. A rltionl dtbs holding pproximtly 12, physico-chmicl rcords for bottom sdimnts, suspndd prticult mttr (SPM) nd wtr, plus high rsolution bthymtric, rsidnc-tim nd sdimntologicl informtion hs bn constructd from th LOCS survy dt. Fils r structurd in mnnr which prmits rtrivl in ny combintion, for xmpl llowing th simultnous intrrogtion of multilmnt sdimnt gochmicl dt nd surficil lithofcis dt. A summry of th informtion currntly vilbl on th dtbs is outlind blow. 5.1: Smpl loclity dtils. Much of th gochmicl, sdimntologicl nd hydrodynmic informtion within th ODA- LOCS dtbs is drivd from fild msurmnts nd subsqunt lbortory nlyss of mtril from 48 smpling sttions, d d MB1- MB48, in th inshor wtrs of Mombs. Th position of ch sttion ws scrtind during th fild survy using non-diffrntil GPS with n oprting rsolution of 3 m. A fil of smpl coordints (rcordd in globl lt-long formt), to which ll othr dtfils r linkd, forms fundmntl componnt of th dtbs. On rtrivl of physico-chmicl dt for ny MBcodd sit, th pproprit sing nd northing * * 2

5 r utomticlly ppndd to th hd of th listing or fil. Convrsion of sit coordints to locl dtum is possibl intrctivly, thus llowing th position of smpling sits to b sily trnsfrrd onto ny Knyn mp. Th distribution of smpling sttions within th inshor wtrs of Mombs is typiclly projctd t th strt of ny intrrogtiv ODA-LOCS GIS sssion (s Figs. 5-8). During th sssion, ttribut tbls of multi-lmnt gochmicl, sdimntologicl or hydrodynmic dt for ny individul sit cn b rtrivd using th ARCVIEW informtion fcility, which is ctivtd by clicking th pproprit icon on th sit of intrst using th mous. 5.2: Sdimnt lithofcis dt. Th surficil lithofcis informtion vilbl within th ODA-LOCS GIS is summrisd in Figur 3, showing dscriptiv fcis-typs bsd on grin siz nlysis of smpls from sttions MB1-MB48. Surficil sdimnts for grnulomtric nlysis wr collctd using Vn Vn grb smplr. Ths wr wt-sivd into 1 frctions rnging from >2mm- 63 pm in siz. Th <63 pm frction ws thn furthr frctiond by Sdigrph. Intrpoltion of informtion btwn grb-smpling sits ws chivd with th ssistnc of sid-scn sonr nd shllowsismic dt providd by th Proudmn Ocnogrphic Lbortory (POL) nd th UK Admirlty. Ths dtfils hv not, howvr, bn incorportd indpndntly within th ODA- LOCS GIS. 5.3: Bthymtric nd hydrodynmic dt. Th high-rsolution bthymtric dt hld on th ODA-LOCS GIS for th nrshor nd inshor wtrs of Mombs (Fig. 4) wr cquird by combining pr-xisting UK Admirlty nd POL sid-scn sonr dt with soundings tkn during BGS-KMFRI survy in Sptmbr Thr-dimnsionl projction of th bthymtric dt is possibl, fcilitting volumtric clcultions for individul crk systms. This, in conjunction with vilbl currnt nd tidl dt, provids bsis for 3-D ocnogrphic modlling. A synoptic mp of hydrodynmic nvironmnts gnrtd using currnt, tidl nd modlld wtr rsidnc-tim dt, is vilbl on th ODA-LOCS GIS. Full dtils of th modlling mthodology usd to gnrt this fil r providd by Rs t l. (1996). 5.4: Intrfcil sdimnt chmistry. Dtfils dpicting th chmicl composition of inshor nd nrshor sdimnts constitut th lrgst singl componnt of th ODA-LOCS dtbs. Intrfcil sdimnt dt obtind through XRF, GC nd GCMS nlysis of th upprmost 2 cm of grvity nd piston cors for LOCS sits MB 1-MB48 r hld within singl ttribut fil (Mommsul). Rtrivl of this fil utomticlly prompts th disply of ll MB smpling points within viw. Ths cn thn b colour-clssifid intrctivly (typiclly using fiv-clss systm) to portry th concntrtion of ny spcifid lmnt, ithr on point-sourc bsis, or s continuous (intrpoltd) surfc. A tbulr disply of loctionl nd multi-lmnt dt for ny singl smpling sttion cn b obtind by ctivting th ARCVIEW informtion icon ovr th sit of intrst (s dscribd in sction 5.1 nd illustrtd in Figur 5). Intrfcil sdimnt dt r hld for th mjor oxids SOz, TiOz, AlzOs, Fz3, MnO, MgO, CO, N,O nd P2s, nd th trc lmnts Ni, Cu, Zn, Cr, V, CO, Sr, Zr, MO, Pb, B, Cd, As nd Sn. Orgnic dtrminnds includ n-lkns, polycyclic romtic hydrocrbons nd orgnochlorins (with limitd sptil covrg). 5.5: Chmo-strtigrphic dt. Grvity or piston cors of up to 1 mtr in lngth wr rcovrd from pproximtly 4 Mombs smpling sttions during th BGS- KMFRI survy. Sub-sctioning nd subsqunt XRF nlysis of ths cors t rsolution rnging from 2-5 cm hs yildd multi-lmnt dt for ovr 2 sub-surfc sdimnt smpls, dtbsd in sris of discrt ttribut fils. Accss to th downcor multi-lmnt dt for ny individul sttion is chtvd vi th intrfcil sdimnt tbl Mommsul, by highlighting th sit numbr of intrst with th cursor s illustrtd in Figur 6. Th prsnttion of grphic downcor profil is subsquntly possibl for tht lmnt originlly colour codd within th viw (Fig. 7). 5.6: Chmistry of mrin wtr nd suspndd prticult mttr (SPM). Dt rgrding th bsic physico-chmicl proprtis (tmprtur, conductivity, slinity, turbidity, ph, Eh nd dissolvd oxygn) of th mid-wtr column in th inshor nd nrshor wtrs of Mombs wr collctd using PHOX 92 sond nd dtloggr. Trc mtl dt for limitd suit of lmnts (Cd, Pb, Zn, Cu, Ni 3

6 nd Cr) for.45 pm filtrd swtrs, cquird by nodic stripping voltmmtry, r incorportd longsid th physico-chmicl dt in singl fil. All r viwd in fshion idnticl to tht dscribd for intrfcil sdimnt dt. This ntils () gnrtion of viw showing smpling loclitis (b) rtrivl of th pproprit dtfil (Mom-wtr) nd (c) colour clssifiction of smpling sits for ny singl wtr prmtr slctd. Suspndd prticult mttr (SPM) ws collctd from th mid-wtr column t ll Mombs smpling sttions by prssur filtrtion of 1 litr of wtr through.45 pm cllulos ctt mmbrn. Anlyticl dt (cquird by ICP-MS) for Mn, CO, Cr, As, Ni, Cu, Zn nd V r vilbl on th ODA-LOCS dtbs in discrt ttribut fil, cssd in th mnnr dscribd bov for wtr nd intrfcil sdimnt. 5.7: Photogrphic nd rltd sit informtion. Th storg of photogrphic informtion showing fild smpling loclitis, cor strtigrphy nd rltd sit informtion is possibl through th downloding of scnnd imgs s Pict-fils. Exmpls of th rng of digitl photogrphic informtion vilbl on th dtbs r providd in Willims t l. (1996). 6: APPLICATIONS AND FUTURE DEVELOPMENT. Although th ODA-LOCS dtbs rmins undr dvlopmnt, wid rng of pplictions of dirct rlvnc to futur nvironmntl plnning nd ICZM in th Mombs costl r cn rdily b idntifid. Ars of invstigtion which show prticulr potntil includ:- Li) Evlution of rltionshim btwn onshor contminnt point-sourcs n d inshorhrshor wtr nd sdimnt qulity. Idntifiction of th dominnt point-sourcs of nrshor mrin contmintion in th Mombs r is vitl prcursor to th formultion of ffctiv dischrg control nd monitoring progrmms. In ddition to dt dpicting th position of hot-spots for rng mtls nd orgnic contminnts in th inshorhrshor zon, th ODA-LOCS dtbs holds full invntory of industris within Mombs municiplity, clssifid by ctivity (Fig. 8). Corrltion of th gochmicl signturs rcordd in pollutd wtrs or sdimnt ginst th composition of dischrgs from industril instlltions rchivd on th GIS my prov usful for this purpos. Furthr vlution of this ppliction following th nsfr of th ODA-LOCS dtbs to KMFRI is strongly rcommndd. fii) Modlling nd mdiction of contminnt dismrsl ot hwvs nd t hir significnc tq prsnt nd futur costl-zon/wtr us plnning. Hydrodynmic modls rlting to th disprsl of quous nd prticult contminnts mnting from industril point-sourcs in th inshor crk systms of Mombs hv bn dvlopd by Rs t 1 (1996) nd cn b ccssd in simplifid form vi th ODA-LOCS GIS. Ths modlld contminnt flow-pths my prov prticulrly vlubl in th siting of outlts for trtd domstic wst or othr contminnt dischrgs. Within th contxt of ICZM, th dlintion of inshor wtrs impctd by contminnt disprsl plums my b of vlu whn dsignting pproprit rs for qucultur, rtisnl fishris or rcrtionl wtr us. Th potntil of th ODA-LOCS GIS for idntifying nd voiding nvironmntl conflicts in this mnnr should b mphsisd during mrkting of th systm to locl nd cntrl govrnmnt plnning gncis. Th ODA-LOCS GIS is schduld to b trnsfrrd to KMFRI during 1997, following forml dmonstrtion nd workshop in Kny. Following trnsfr, it is nticiptd tht th utility of th systm will b progrssivly incrsd through rgulr updting of xisting dtfils nd th instlltion of dditionl goscintific, nvironmntl nd lnd/wtr dtsts. 7: ACKNOWLEDGEMENTS All fild survys undrtkn by BGS in Mombs wr supportd both logisticlly nd scintificlly by stff of th Kny Mrin nd Fishris Rsrch Institut. Prticulr thnks r du to Mr K K Kiru, Knyn coordintor of th LOCS progrmm, nd Mr A C Yob, principl scintific countrprt. Dt from th EAF/6 dtbs ws providd for BGS us by courtsy of UNEP OCAlpAC nd KMFRI. Spcil thnks r xtndd to Mr D Vn Spybrok for kindly ssisting in th digitl trnsfr of this informtion, nd for th provision of usful dvic nd guidnc to BGS stff working in Kny. Funding for ll work crrid out undr th LOCS projct ws providd by th UK ODA 4

7 I. 9 (Environmnt Division) undr R&D contrct R : REFERENCES J G Rs, T M Willims, M Nguli, K K Kiru nd A C Yob: Contminnt trnsport nd storg in th sturin crk systms of Mombs, Kny. British Gologicl Survy, Ovrss Gology Sris Tchnicl Rport WC T M Willims, J G Rs, K K Kiru & A C Yob: Assssmnt of contmintion by mtls nd slctd orgnic compounds in costl sdimnts nd wtrs of Mombs, Kny. British Gologicl Survy, Ovrss Gology Sris Tchnicl Rport WC

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