Investigating organic matter in Fanno Creek, Oregon, Part 1 of 3: estimating annual foliar biomass for a deciduous-dominant urban riparian corridor

Journal of Hydrology
Clean Water Services
By: , and 

Links

Abstract

For this study, we explored the amount, type, and distribution of foliar biomass that is deposited annually as leaf litter to Fanno Creek and its floodplain in Portland, Oregon, USA. Organic matter is a significant contributor to the decreased dissolved oxygen concentrations observed in Fanno Creek each year and leaf litter is amongst the largest sources of organic matter to the stream channel and floodplain. Using a combination of field measurements and light detection and ranging (LiDAR) point cloud data, the annual foliar biomass was estimated for 13 stream reaches along the creek. Biomass estimates were divided into two sets: (1) the annual foliage available from the entire floodplain overstory canopy, and (2) the annual foliage overhanging the stream, which likely contributes leaf litter directly to the creek each year. Based on these computations, an estimated 991 (±22%) metric tons (tonnes, t) of foliar biomass is produced annually above the floodplain, with about 136 t (±24%) of that foliage falling directly into Fanno Creek. The distribution of foliar biomass varies by reach, with between 150 and 640 t/km2 produced along the floodplain and between 400 and 1100 t/km2 available over the channel. Biomass estimates vary by reach based primarily on the density of tree cover, with forest-dominant reaches containing more mature deciduous trees with broader tree canopies than either wetland or urban-dominant reaches, thus supplying more organic material to the creek. By quantifying the foliar biomass along Fanno Creek we have provided a reach-scale assessment of terrestrial organic matter loading, thereby providing land managers useful information for planning future restoration efforts.

Study Area

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Investigating organic matter in Fanno Creek, Oregon, Part 1 of 3: estimating annual foliar biomass for a deciduous-dominant urban riparian corridor
Series title Journal of Hydrology
DOI 10.1016/j.jhydrol.2014.06.054
Volume 519
Issue Part D
Year Published 2014
Language English
Publisher Elsevier
Contributing office(s) Oregon Water Science Center
Description 8 p.
First page 3001
Last page 3009
Country United States
State Oregon
Other Geospatial Fanno Creek
Datum North American Datum of 1983
Projection Universal Transverse Mercator projection
Online Only (Y/N) N
Additional Online Files (Y/N) N