Eawag_09041 ·.~·PLOS.. I ONE RESEARCH ARTI CLE Evaluation of Spatial Pattern of Altered Flow Regimes on a River Network Using a Distributed Hydrological Model Masahiro Ryo1 ""*, Yuichi lwasaki2Db, Chihiro Yoshimura\ Oliver C. Saavedra V.1 1 Department of Civil Engineering, Tokyo Institute of Technology, Meguro-ku, Tokyo, Japan, 2 Department of Fish, Wildlife, and Conservation Biology, Colorado State University, Fort Collins, Colorado, United States of America aa Current Address: Department of Aquatic Ecology, Eawag, Duebendor1, Switzerland ab Current Address: Research Centerfor Life and Environmental Sciences, Toyo University, Oura, Gunma, Japan @ *
[email protected] CrossMark ckk b updltes Abstract Alteration of the spatial variability of natural flow regimes has been less studied than that of b OPEN ACCESS the temporal vari ability, despite its ecological importance for river ecosystems. Here, we Citation: Ryo M, Iwasaki Y, Yoshimura C, Saavedra aimed to quantify the spatial patterns of flow regime alterations along a river network in the V. OC (20 15) Evah.etion of Spatial Pattern of Altered Sagami River, Japan, by estimating ri ver discharge under natural and altered flow condi- Fbw Regmes on a River Network Using a tions. We used a distributed hydrological model, which simulates hydrological processes Distributed Hydrological Model. PloS ONE 10(7): spatiotemporally, to estimate 20-year daily river discharge along the river network. Then, 33 e01 33833. doi:10. 1371/purnal.pone.0133833 hydrologic indices (i.e., Indicators of Hydrologic Alteration) were calculated from the simu- Editor: Zhong Ke Gao, lian;n University, CHINA lated discharge to estimate the spatial patterns of their alterations. Some hydrologic indices Received : January 8, 2015 were relatively well estimated such as the magnitude and timing of maximum flows, monthly Accepted : July 2, 2015 median flows, and the frequency of low and high flow pulses.