Services and Analysis

SISKA ins­tru­ments under­ground cavi­ties with various sen­sors to moni­tor phy­si­cal and che­mi­cal para­me­ters (flow rates, elec­tri­cal conduc­ti­vi­ty, tem­pe­ra­ture, radon, CO2, methane, noise, etc.). SISKA offers its ser­vices for set­ting up hydro­geo­lo­gi­cal sur­veys and moni­to­ring ground­wa­ter qua­li­ty. Wire­less data trans­mis­sion means that the mea­su­re­ments can be consul­ted in real time and alarm sys­tems set up in the event of floo­ding or exces­si­ve­ly high gas concen­tra­tions.

As part of impact stu­dies, SISKA moni­tors recon­nais­sance drilling and accom­pa­nies geo­phy­si­cal inves­ti­ga­tions.

SISKA also spe­cia­lises in moni­to­ring and inter­pre­ting hydro­geo­lo­gi­cal data from explo­ra­to­ry bore­holes. It can also sup­port geo­phy­si­cal inves­ti­ga­tions.

SISKA spe­cia­lises in sur­veying and dra­wing up geo­lo­gi­cal maps and topo­gra­phi­cal plans of under­ground sites (mines, quar­ries, caves, etc.). Using cut­ting-edge tech­no­lo­gy, the SISKA mea­sures and maps under­ground cavi­ties with a degree of pre­ci­sion adap­ted to each need (from quick sketches to detai­led plans).

The appli­ca­tion of new tech­no­lo­gies to cavi­ty topo­gra­phy (LiDAR, pho­to­gram­me­try) involves the deve­lop­ment of map­ping, data mana­ge­ment and archi­ving tech­niques. SISKA is focu­sed on main­tai­ning exis­ting data while deve­lo­ping new acqui­si­tion and visua­li­sa­tion methods.

Mapping and inventory of karstic areas

The « Karst » map is pro­du­ced based on an inven­to­ry of know­ledge (geo­lo­gy, hydro­lo­gy, vege­ta­tion) that makes it pos­sible to iden­ti­fy regions prone to kars­ti­fi­ca­tion that the­re­fore require appro­priate mana­ge­ment. These data serve as a basis for applying the EPIK method for the pro­tec­tion of ground­wa­ter.

Inven­to­ry of sin­kholes and lapiaz inte­grates local know­ledge (spe­leo­lo­gists, forest ran­gers, .…) and geo­gra­phi­cal ana­ly­sis, com­bi­ning soil map­ping, detai­led stra­ti­gra­phy and geo­lo­gi­cal struc­tures. This data is used to iden­ti­fy areas of geo­lo­gi­cal inter­est with a view to pro­tec­ting them.

Analysis of collapses and recommendations

The pre­sence of under­ground voids is often pro­ble­ma­tic, for example when buil­ding a wind tur­bine, a tun­nel or a house. Explo­ra­tion of a kars­tic net­work and its topo­gra­phi­cal sur­vey are used to locate the pre­sence of a cavi­ty close to infra­struc­ture. Detec­ting unk­nown cavi­ties at depths grea­ter than 15 or 20 metres is often dif­fi­cult. Howe­ver, in col­la­bo­ra­tion with various part­ners, SISKA is using and deve­lo­ping various geo­phy­si­cal methods to locate cavi­ties from the sur­face. Our expe­rience enables us to pro­vide prac­ti­cal recom­men­da­tions for mana­ging these cases.

SISKA is a pio­neer in applying 3D tech­no­lo­gies to model­ling under­ground objects (geo­lo­gy, mines, caves, under­ground struc­tures) and ground­wa­ter.

In kars­tic regions, the flow of springs and rivers is control­led by the hydro­geo­lo­gi­cal func­tio­ning of the under­ground karst. A 3D ana­ly­sis of the sub­ter­ra­nean layers enables us to assess flow rates and the basins that feed the springs. This know­ledge is essen­tial for asses­sing the risk of floo­ding during excep­tio­nal rain­fall events, and the risk of drought.

SISKA offers digi­tal solu­tions for simu­late the beha­viour of ground­wa­ter These results are impor­tant for the construc­tion of under­ground struc­tures. They also pro­vide impor­tant insights for sur­face water and natu­ral hazard mana­ge­ment and impact stu­dies, for example the deter­mi­na­tion of resi­dual flowsTo do these simu­la­tions, SISKA uses a num­ber of soft­ware pro­grammes such as SWMM5 or RS Minerve.

SISKA main­tains a field inven­to­ry of pol­lu­ted cavi­ties and dolines and adds them to the regis­ter of pol­lu­ted sites. Some of these cavi­ties have been known for a long time, but pre­cise infor­ma­tion is often lacking (volume of waste, access, type of waste).

A inves­ti­ga­tion report is drawn up for each region concer­ned, inclu­ding a des­crip­tion of the site, a map of the cavi­ty, pho­to­graphs, the volume and type of waste and a reme­dia­tion bud­get.

In coor­di­na­tion with the autho­ri­ties (Com­munes, can­tons, Confe­de­ra­tion, army), the sites are reme­dia­ted using spe­cia­li­sed equip­ment and, with the sup­port of civil ser­vants, the waste is sor­ted and taken to repro­ces­sing centres. Once the reme­dia­tion is com­plete, a report is sub­mit­ted to the autho­ri­ties.

SISKA offers a ser­vice for iden­ti­fying bones found in kars­tic envi­ron­ments.

Link to Archaeo­zoo­lo­gy com­pe­tence

SISKA sup­ports and car­ries out hydro­geo­lo­gi­cal tra­cing tests by injec­ting a non-toxic, gene­ral­ly colou­ring sub­stance into the envi­ron­ment (loss, sin­khole, cave, etc.). Field fluo­ro­me­ters, auto­ma­tic sam­plers and fluo­ro­sen­sors are used to iden­ti­fy the sources connec­ted to the injec­tion point(s), and to cha­rac­te­rise the link (speed, res­ti­tu­tion rate, etc.). SIS­KA’s fluo­res­cence ana­ly­sis labo­ra­to­ry can quan­ti­fy tra­cer concen­tra­tions of less than µg/l.