WETLAND AND RIVER CROSSINGS: GENERIC CROSSING PROCEDURE

Transcription

1 METHOD STATEMENT Wetland and River Crssings METHOD STATEMENT WETLAND AND RIVER CROSSINGS: GENERIC CROSSING PROCEDURE Issued fr Review Semane Jnes & Wagener Rev. Date Reasn fr Issue Prepared by Checked by Client Apprval Categry Cde Categry Cde Descriptin Area Cde SOUTH AFRICA 102-NLG-023 Dcument Type Generic Wetland and River Crssings Prcedure

2 GENERIC METHOD STATEMENT: WETLAND ANR RIVER CROSSINGS TABLE OF CONTENTS CONTENTS 1.0 PURPOSE SCOPE OF WORK GENERAL MEASURES CONSTRUCTION PROCEDURES Seepage Wetlands START DATE AND DURATION OF CONSTRUCTION MATERIALS AND EQUIPMENT TO BE USED MOVEMENT OF MATERIAL AND EQUIPMENT FROM THE WATERCOURSE CROSSINGS HANDLING OF ALL MATERIALS, EXCESS MATERIALS AND WASTE MATERIALS REHABILITATION NOTES... 7 Page 2 f 7

3 1.0 Purpse The purpse f this dcument is t describe and define the general methd used fr Wetland and River Crssings at the New Larg Prject. 2.0 Scpe f wrk This prcedure describes methd f safely remving 150mm f tpsil, excavating fr subsurface drainage r undercut fr rad cnstructin, ftings and plinths, layerwrks fr pavement structure, backfill and cmpact arund structures, cnstruct cncrete wrks, and reinstatement f Wetland and River Crssings at the New Larg Prject. The intentin is t undertake the wrks utilising dedicated and well trained teams t ensure that the wrks are prgressed in a safe and envirnmentally respnsible manner. 3.0 General Measures The fllwing general measures shuld be implemented during cnstructin: The area f disturbance shuld be kept t a minimum t allw clearing f the cnstructin right f way, excavatin, layerwrks, cnstruct cncrete wrks, backfill, t restre the cnstructin right f way. This shuld nt exceed : The cnstructin ftprint width must be kept t a minimum, fr bth the wetland and the river crssing. A sequential cnstructin strategy shuld be fllwed, i.e. Cnstructin shuld be immediately fllwed by rehabilitatin; Sils excavated in the wetland shuld be stred in sequence and nt in the wetland perimeter ; Sils must be replaced in same sequence as excavated; Sil surfaces shuld nt be left pen fr lengthy perids t prevent ersin. Sds must be stred and placed back immediately after subsils have been backfilled. Page 3 f 7

4 Strm water management measures shuld be implemented; Where pssible, cnstructin shuld take place during the dry seasn. Weather frecasts frm the Suth African Weather Bureau f up t three days in advance must be mnitred n a daily basis t avid expsing sil r building wrks during a strm event. Apprpriate actin must be taken in advance t prtect cnstructin wrks shuld a strm event be frecasted; Apprpriate ersin and sediment cntrl measures shuld be implemented. Sediment barriers shuld be cnstructed acrss the entire cnstructin right f way at all watercurse crssings where necessary t prevent sediment flw int the watercurse; Vegetatin and sil shuld be retained in psitin fr as lng as pssible, and shuld nly be remved immediately ahead f cnstructin / earthwrks in any specific area; Remve nly the vegetatin where essential fr the cntinuatin f cnstructin f the cnveyr/access rad. D nt allw any disturbance t the adjining natural vegetatin cver r sils. 4.0 Cnstructin Prcedures 4.1 Seepage Wetlands Due t the sensitivity f the wetlands, a methd is prpsed t install flw drains either side f the cnstructin area fr water t flw in bth directin at the wetland. This will ensure that the water flw in the wetlands will nt be jepardised by the any cnstructin prcedure. 5.0 Start Date and Duratin f Cnstructin T be cnfirmed by the appinted civil cntractr. 6.0 Materials and Equipment t be used Cnstructin plant The fllwing plant is likely t be used during cnstructin and specific details shuld be prvided in the methd statements n which plant will be used in the varius cnstructin methdlgies at implementatin phase: Excavatrs (20 t 30 tn) Rllers suitable fr the cmpactin f trenches Page 4 f 7

5 Graders Type D6 Dzers TLB s Tipper trucks (10 m3) r equivalent ADT s Watercarts Mbile crane Material A detailed list f material t be used in the watercurses during cnstructin shuld be included in the methd statement accrding t the specificatins, Bill f Quantities and Drawings. 7.0 Mvement f Material and Equipment frm the Watercurse Crssings Access rads will be cnstructed prir t any cnstructin wrk at the wetland areas, indicated n the drawings. The access rad will cleared and the fill material will be ended tipped t reduce the cnstructin ftprint. The alignment f the access rad will be as per permanent service rad. Bulk excavated material will be transprted n the access rad with Tipper Trucks r ADT s and will be stckpile utside the wetland r river crssing perimeter. 8.0 Handling f all Materials, Excess Materials and Waste Materials Strage N cnstructin materials may be stred r dispsed f within the delineated wetlands r within the buffer zne f 30 m frm the wetlands. N cncrete batching may take place within the delineated wetlands r within the buffer zne f 30 m frm the wetlands. N refuelling may take place within the delineated wetlands r within the buffer zne f 30 m frm the wetlands. Dispsal All material must be remved t a designated area, r a licenced waste dispsal facility, if it cannt be re-used. Page 5 f 7

6 9.0 Rehabilitatin In areas where cnstructin activities have been cmpleted and n further disturbance is anticipated, rehabilitatin and re-vegetatin shuld cmmence as sn as pssible. Fr channelled watercurses: Prfile the banks f the watercurse ver the disturbed areas t an acceptable slpe and replace tpsil; Where requested by the engineer, cver the disturbed area at watercurse crssings with a bidegradable wven jute getextile ersin cntrl blanket (e.g. Gejute); Where requested by the engineer, ensure that the ersin cntrl blanket is well anchred burying the edges and pegging the rest f the material n a 1 m2 grid ver its entire area. Use nly wden pegs; Take plugs f indigenus sedge and grass material frm the adjacent areas; Plant these plugs n a 50 x 50 cm grid in hles punched thrugh the ersin cntrl blanket. Add apprpriate fertiliser in the bttm f the hle prir t planting; Water the planted plugs thrughly immediately after planting and cntinue t water every three days in the absence f mre than 10 mm f rainfall until plants are established. Re-vegetatin f disturbed areas must be undertaken with indigenus species and in accrdance with the instructins issued by the Envirnmental Cntrl Officer (ECO). Replanting activities shuld be undertaken at the end f the dry seasn (middle t end September) t ensure ptimal cnditins fr germinatin and rapid vegetatin establishment; Shuld plants nt successfully establish within tw grwing seasns after the first planting, new plant material shuld be prvided; Any weed r alien species that germinates during the cntract perid shuld be cleared by hand befre flwering; Any ersin channels develped during the cnstructin perid shuld be apprpriately backfilled (and cmpacted where relevant) and the areas restred t a cnditin similar t the cnditin befre the cnstructin ersin ccurred. Page 6 f 7

7 10.0 Ntes 1. All cnstructin and reinstatement activities in wetland areas t cmply in strict accrdance t the EMP and specific requirements frm DWAF. 2. A detailed methd statement will be drafted fr authrisatin by all parties cncerned fr each wetland t be crssed. The ECO will sign-ff these after cmpletin f each crssing as required by the Water Use License. 3. The ECO will cntinually update a wrking wetlands table indicating prgress f wetland authrisatins and crssing cmpletin. Page 7 f 7