The Rimba Raya Biodiversity Reserve REDD Project

For a complete report on the Carbon Assessment Surveys, seeAnnex 5.Canal Depth SurveyA field survey was conducted in order to assess the canal depthand drainage practices of the KUCC oil palm estate. Drainagedepth is an important component in the methodology for thepurpose of calculating the baseline.measuring water depth, siting land grade and recordingmeasurements in a field notebook. Care was taken to accuratelysite original land grade which was often situated below roadgrade by at least 0.5 meters so that canal depths were not over-­estimated.KUCC lies at the northern extent of Rimba Raya and is situatedapproximately 10-­‐20 meters higher in elevation than the projectarea. The land in KUCC grades east towards the Seruyan Riverand south to the deep peats of Rimba Raya's carbon accountingarea. In low-­‐lying areas, especially along rivers draining to theSeruyan, a network of drainage canals have been cut throughpeat swamps where oil palm has been planted. These areas werethe focus of the field survey aimed at systematically measuringdrainage canal depths.Survey target locations were established by interpreting peatdrainage areas on 10-­‐meter resolution SPOT5 satellite imagery.Seventy-­‐five target locations were identified, entered intoGarmin GeoXT GPS units and mapped on hardcopy field maps.Two two-­‐person survey teams spent five days during August 9-­‐18traversing plantation roads on motorbike to reach targetlocations. Some target locations were situated in a mosaic of highground areas (non-­‐peat) and some were unreachable as newlycut roads could not be accessed. Areas of newly cut peat that hadnot yet been planted in oil palm were excluded from the survey.A total of 50 locations distributed throughout KUCC peatlandswere surveyed. Teams used centimeter measuring tapes andwooden stakes to measure canal depth below-­‐water and above-­waterto the natural land grade. Team members divided tasks ofMeasuring primary drainage canal depthResults showed that canal depth in the KUCC peatland areasalready planted in oil palm were 1.44 meters averaging allprimary, secondary and tertiary drainages. The four primarydrainages measured were all >2 meters deep (average 2.23meters). These data exclude newly opened areas of deeper peatwhich had not yet been planted in oil palm. Three of these areaswere visited during an initial survey, and new drainage canalswere measured at >3 meters deep (average 3.40 meters).90