Consulting

Un­ders­tan­ding karst ground­wa­ter re­quires a 3D as­sess­ment of the geo­lo­gy. KARSYS is a de­duc­tive ap­proach ba­sed on the geo­lo­gy of a site and the hy­drau­lic prin­ciples go­ver­ning kars­ti­fi­ca­tion. Once a site is de­fi­ned, SISKA de­ploys a 4 step ap­proach: (i) iden­ti­fying the kars­tic pro­per­ties of the aqui­fers, (ii) es­ta­bli­shing a 3D geo­lo­gi­cal mo­del of aqui­fer units, (iii) ge­ne­ra­ting a 3D hy­dro­geo­lo­gi­cal mo­del through in­te­gra­tion of hy­dro­lo­gi­cal da­ta and (iv) iden­ti­fi­ca­tion and de­li­mi­ta­tion of flow sys­tems.
This re­sults in:

• the de­li­mi­ta­tion of spring ba­sins;
• the vo­lu­me­tric as­sess­ment of ground­wa­ter re­sources;
• a mo­del of un­der­ground wa­ter flow paths.

Vi­sual­KAR­SYS, is a free on­line ser­vice for buil­ding and vie­wing KARSYS mo­dels.

Karst­MOD (hy­dro­lo­gi­cal and hy­drau­lic mo­dels) makes it pos­sible to si­mu­late ground­wa­ter dy­na­mics quan­ti­ta­ti­ve­ly, and as­sess re­charge (ef­fec­tive in­fil­tra­tion), sto­rage and flow at one or more out­lets.

SISKA ap­plies me­thods and tools to stu­dy the vul­ne­ra­bi­li­ty of ground­wa­ter,the de­li­mi­ta­tion of pro­tec­tion zones and the search for sources of pol­lu­tion.

In col­la­bo­ra­tion with other spe­cia­list part­ners, SISKA of­fers so­lu­tions for pros­pec­ting and ex­ploi­ting ground­wa­ter. This in­cludes the ana­ly­sis of spring flows and si­mu­la­ting of flows un­der dif­ferent sce­na­rios (me­teo­ro­lo­gi­cal, an­thro­po­ge­nic im­pacts, ex­ploi­ta­tion stra­te­gies).

SISKA pro­poses spe­ci­fic ap­proaches for as­ses­sing the ha­zards karst poses on construc­tion and va­rious ac­ti­vi­ties.

Civil engineering and karst

Du­ring construc­tion, par­ti­cu­lar­ly un­der­ground (tun­nels, gal­le­ries, re­ser­voirs...), the kars­tic en­vi­ron­ment can present struc­tu­ral pro­blems. These in­clude unex­pec­ted voids, pres­su­ri­zed wa­ter and the pre­sence of poor­ly conso­li­da­ted se­di­ments. Using the Karst ALEA me­thod, the SISKA can pre­dict po­ten­tial ha­zards, pro­pose pro­tec­tive mea­sures to mi­ni­mise them and make re­com­men­da­tions to ma­nage pro­blems should they oc­cur.

Wind turbines and karst

SISKA is de­ve­lo­ping me­thods for as­ses­sing and sup­por­ting the ins­tal­la­tion of wind tur­bines in karst re­gions. The aim is to mi­ni­mise the risks of karst to in­fra­struc­ture sta­bi­li­ty. An in­for­ma­tio­nal bro­chure on this is­sue has been pu­bli­shed by the SSS.

Infiltrations

In an ur­ban kars­tic en­vi­ron­ment, the fe­de­ral re­com­men­da­tion to in­fil­trate grey wa­ter (roof and road wa­ter) is pro­ble­ma­tic be­cause this in­fil­tra­tion may fa­ci­li­tate col­lapses. SISKA can draw up col­lapse ha­zard maps and as­sess­ments. In the event of a col­lapse, tar­ge­ted re­com­men­da­tions can be is­sued.

If in­fil­tra­tion sites are se­lec­ted, SISKA can is­sue re­com­men­da­tions on ac­cep­table in­fil­tra­tion flow rates and condi­tions.

Collapse hazards

The kars­tic sub­sur­face contains nu­me­rous ca­vi­ties, so­me­times co­ve­red by a thin layer of soil. Col­lapses are the­re­fore not un­com­mon. SISKA can pro­duce site spe­ci­fic col­lapse ha­zard maps and as­sess­ments.

Geothermal

The spe­ci­fic cha­rac­te­ris­tics of karst can lead to poor constraints on geo­ther­mal pro­jects. In­deed, due to the si­gni­fi­cant cir­cu­la­tion of air and wa­ter, kars­tic mas­sifs are col­der than other en­vi­ron­ments. Ho­we­ver, kars­tic springs drain geo­ther­mal heat and re­present an in­ter­es­ting re­source. SISKA has unique ex­per­tise that en­ables it to as­sess ener­gy po­ten­tial and de­ve­lop a stra­te­gy for geo­ther­mal ex­ploi­ta­tion in car­bo­nate re­gions.

SISKA can pre­pare pres­crip­tion maps for the ins­tal­la­tion of geo­ther­mal probes ba­sed on ground­wa­ter vul­ne­ra­bi­li­ty cri­te­ria.

The construc­tion pro­jects and va­rious hu­man ac­ti­vi­ties (tun­nels, gal­le­ries, roads, wind tur­bines, geo­ther­mal ener­gy, in­fil­tra­tion of grey wa­ter, etc.) can have an im­pact on the kars­tic en­vi­ron­ment. SISKA is spe­cia­li­sed in as­ses­sing and mi­ni­mi­sing these im­pacts in ac­cor­dance with the Or­di­nance on En­vi­ron­men­tal Im­pact As­sess­ment (OEIE).

SISKA has de­ve­lo­ped a se­ries of tools and me­thods for such as­sess­ments (Vi­sual KARSYS, Karst ALEA and others).

Impact on groundwater

In kars­tic en­vi­ron­ments, al­most all rain­wa­ter in­fil­trates the sub­soil and, af­ter a few days to weeks, emerges from springs that then feed ri­vers. De­ve­lop­ments and struc­tures can mo­di­fy the water's flow re­gime and qua­li­ty. These changes can be cri­ti­cal for drin­king wa­ter catch­ments, ri­vers and un­der­ground aqua­tic fau­na. SISKA can as­sess these im­pacts and seek so­lu­tions that mi­ni­mise them.

Impact on underground fauna

The un­der­ground en­vi­ron­ment is home to a spe­ci­fic and va­ried fau­na in­clu­ding se­ve­ral en­de­mic spe­cies. Un­der­ground ha­bi­tats are ve­ry stable be­cause they are re­la­ti­ve­ly unaf­fec­ted by ex­ter­nal va­ria­tions (cli­mate, ur­ba­ni­sa­tion, etc.). Ho­we­ver, their in­ha­bi­tants are ve­ry sen­si­tive to change. SISKA can as­sess the fau­na present, the sen­si­ti­vi­ty of the ha­bi­tats and the po­ten­tial or ac­tual in­fluences of a de­ve­lop­ment or construc­tion pro­ject.

Impact on the underground climate

The tem­pe­ra­ture and hu­mi­di­ty (>98%) un­der­ground is al­most constant year-round. Any dis­rup­tion to these cli­ma­tic condi­tions will have an im­pact on the cave, the fau­na and any ar­chaeo­lo­gi­cal ar­te­facts found there. Fur­ther­more, the un­der­ground at­mos­phere is of­ten en­ri­ched with CO₂ and ra­don, which can cause pro­blems if the cave is oc­cu­pied for long per­iods (e.g. ar­chaeo­lo­gi­cal ex­ca­va­tions, tou­rist vi­sits). SISKA can mea­sure and mo­ni­tor the cha­rac­te­ris­tics of an un­der­ground cli­mate sys­tem and can the­re­fore as­sess the im­pact of a de­ve­lop­ment or construc­tion pro­ject on cave cli­mate.

Impact on the karstic landscape

Kars­tic land­scapes have been re­co­gni­zed world­wide for their im­por­tance to our na­tu­ral he­ri­tage (18 lo­ca­tions are lis­ted as UNESCO World He­ri­tage sites and nu­me­rous others are lis­ted in the fe­de­ral land­scape in­ven­to­ry). In Swit­zer­land, sin­kholes, po­tholes and caves are of­ten not ex­pli­cit­ly in­ven­to­ried, even though they form part of the country's na­tu­ral he­ri­tage. SISKA can iden­ti­fy these ob­jects, as­sess them and seek so­lu­tions to mi­ni­mise po­ten­tial im­pacts on these fea­tures.

The Karst ALEA me­thod was de­ve­lo­ped spe­ci­fi­cal­ly to as­sess the pro­blems po­sed by kars­tic en­vi­ron­ments du­ring the construc­tion of a struc­ture and the im­pact of the pro­ject on the en­vi­ron­ment. It can be used to pre­dict the po­si­tion and cha­rac­te­ris­tics of kars­tic ca­vi­ties in a li­mes­tone mas­sif. 

It al­so serves as a ba­sis for dra­wing up col­lapse ha­zard maps.

Link to ap­plied me­thods Karst ALEA