A Simple Model To Estimate Carbon Stock Based On River Discharge: Supporting The Next Implementation Of Redd+ In Indonesia Under Paris Agreement Regime

Abstract

Land covers is the main determinant of river discharge rate of a watershed.  The land cover, on the other hand, also contain the carbon stock accumulated above ground over watershed. This relation is very useful in carbon stock monitoring to support Paris Agreement implementation especially for tropical countries where the MRV activities are commonly very expensive. In this research the ordinary least square models were employed at significant level of 95%.  First model was the river discharge, [YD], as the function of rainfall [RAIN] (mm/year) and the acreage of land covers area (ha) namely the forest [FREST], shrub [SRHB], plantation [PLNT], up land crop [UPLND], mix farming [MIXFM], and settlement [SETL]. The second model was to express the carbon stock [YC] (ton/ha) as the function of the [YD].  Data series of [RAIN], [YD] and lands covers of 2011, 2014, 2017 covering 3 watershed (Way Pengubuan, Way Bulok, and Way Besai) lies at Lampung Province, Republic of Indonesia. We employed Minitab 16 for parameter model estimation. The simple models achieved for river discharge was [YD]i=13,612.00 +0.1192[RAIN]I -238,00[FREST]i-129,08[SRHB]i-107.46[PLNT]i-184.16[SETL]i-131.08[UPLND]i-30.97[MIXFM]i-127.01[PADY]i with P=0.000 and R.Sq (adjt) =96.6%; and the carbon stock expressed by [Yc]i=17.2237 - 0.0212 [YD]i with P=0.0006 and the Rsq(adjt)= 0.5283.