Södra Skåne EIA

Gö­te­borg Vat­ten is plan­ning to lay new was­te wa­ter pi­ping between the is­lands in Söd­ra Skär­går­den and a new jun­c­tion po­int at Älv­nab­ben on the main­land. Ge­o­sig­ma is re­s­pon­sib­le for the pre­pa­ra­tion of an en­vi­ron­men­tal im­pact as­sess­ment (EIA), which is to be lod­ged for an ap­p­li­ca­tion for li­cen­ce for the works.

In this pro­cess the­re aro­se, du­ring the sum­mer of 2011, requi­re­ments from the Coun­ty Coun­cil re­gar­ding ex­a­mi­na­tion of sea beds with re­gard to the stock of eelg­rass.

The eelg­rass en­vi­ron­ments are bi­o­ty­pes worthy of pre­ser­va­tion sin­ce they are im­por­tant growth loca­tions for fish and hou­se a high bi­o­lo­gi­cal di­ver­si­ty. The eelg­rass has al­so di­mi­nished shar­ply along the Swe­dish west co­ast over the last 20 ye­ars, pri­ma­rily due to the wa­ter be­co­ming mud­di­er as a re­sult of over-fer­ti­li­sing and inc­re­a­sed bo­at traf­fic. Ma­ny en­vi­ron­ments al­so disap­pe­ar or are da­ma­ged through lei­su­re bo­at traf­fic and dred­ging.

Our Pro­ject Ma­na­ger  the­re­fo­re ex­ten­ded our con­sul­tan­cy ser­vi­ces to in­clu­de diving in or­der to con­firm the sta­tus of pos­sib­le eelg­rass en­vi­ron­ments. The diving was car­ri­ed out un­der ex­cel­lent we­ather con­di­tions. The wa­ter was, ho­we­ver, mud­dy, and at Styr­sö Brat­ten the bo­at traf­fic was in­ten­se whe­re­by diving with tu­bes was preclu­ded. Even with a ho­is­ted diving flag it could not be pre­su­med that tho­se ope­ra­ting the bo­ats un­der­stood the im­por­tan­ce or dis­play­ed the ne­ces­sa­ry con­si­de­ra­tion. The eelg­rass tends to grow no dee­per than 5 m which is why snork­ling was an ex­cel­lent, al­beit mo­re phy­si­cal­ly de­man­ding, al­ter­na­ti­ve. Tran­sects (se­arch li­nes) we­re laid out with align­ment and, in so­me ca­ses, the depth con­tours we­re fol­lo­wed. Tran­sects ac­ross the depth con­tours we­re al­so ma­de. Clo­se to the sho­re­li­ne, in the har­bour for smal­ler ves­sels, it could ra­pid­ly be as­cer­tai­ned that ve­ge­ta­tion was ge­ne­ral­ly non-ex­i­s­tent. Further out to the east, the ve­ge­ta­tion inc­re­a­sed and in­di­vi­du­al eelg­rass plants we­re found along the pi­pe­li­ne st­retch. Furthest out to­wards Don­sösun­det a band of ve­ge­ta­tion had pre­viously been iden­ti­fi­ed ac­ross the pi­pe­li­ne st­retch between the is­lands. A dolphin was used as a po­int of de­par­tu­re and di­ves we­re ma­de at in­ter­vals down to a depth of 4-5 m. The ve­ge­ta­tion con­si­s­ted of a tight­ly grown eelg­rass bed which, to a lar­ge ex­tent, cor­re­s­pon­ded to the area pre­viously iden­ti­fi­ed.