Journal of Geosciences and Geomatics, 2017, Vol. 5, No. 3, 130-135 Available online at http://pubs.sciepub.com/jgg/5/3/4 ©Science and Education Publishing DOI:10.12691/jgg-5-3-4 The Role of Human Activities in Streambank Stability: Lower Sakarya River (NW Turkey) Umit Duru * Geography Department, Sakarya University, Sakarya, Turkey *Corresponding author: umitduru@sakarya.edu.tr Abstract The main objective of this study is to determine historic and current human impacts on streambank stability in Lower Sakarya River. Remote sensing and Geographical Information System techniques with conjunction field works were performed to identify the impact of human alteration on streambank stability in the riverine environment of the eastern portion of Sakarya province. LULC (land use/cover) and historical streambank changes were analyzed from Landsat 1-5 Multispectral Scanner (MSS), Landsat-7 Enhanced Thematic Mapper Plus (ETM+), and Google Earth images between 1995 and 2016. As results, a significant LULC changes have been observed along the buffered zone due to population growth. Recently, change in LULC type from agricultural to urban usage has changed river equilibrium. The stream channel also became more stable and straight as man-made modifications including a hydropower (HES) dam constructed in 2010, which primarily reduced flood frequency, water velocity, stream power, shear stress on sediment particles temporarily deposited along the streambank. After the year of 2010, downstream portion of the dam had experienced narrowing and expanding mid-channel bars. Moreover, the channel has been slightly moved towards east especially along urbanized and sinuous courses. The streambank displacement ranged from 2.9 m to 36 m in the region. Instream mining activities and bridge constructions in the region also disturb active streambanks, which raise a concern about instability of streambank and potential damage to infrastructures. Such studies are extremely important for understanding basic mechanisms of streambank evolution for further river restoration practices. Keywords: streambank stability, LULC, anthropogenic effects, GIS, Sakarya River Cite This Article: Umit Duru, “The Role of Human Activities in Streambank Stability: Lower Sakarya River (NW Turkey).” Journal of Geosciences and Geomatics, vol. 5, no. 3 (2017): 130-135. doi: 10.12691/jgg-5-3-4. 1. Introduction Streambank stability is here defined as the resistance of channel bed to natural and anthropogenic changes, and its resilience through years. Besides natural processes, the rate of streambank stability can be greatly altered by human modifications (channel modifications, reservoir constructions, land use/cover changes etc). Although such activities are crucial for development, they may have adverse effects in riverine environment. Human modified the environment to suite their demand and how people adapt to prevail environment is explained by Human environment interactions by the National Council for Geographic Education and the Association of American Geographers. Instream modifications usually lead to a noticeable decrease in bank erosion; channel migration so far as native species conserved in a riparian zone. Human induced changes in a stream channel may culminate in numerous environmental and socioeconomic consequences including loss of riparian zones and damage in infrastructures. For example, concrete armoring channels demolish the species in riparian areas, and removing riparian vegetation can also alter the morphology and natural dynamics of rivers [1,2]. The rivers response anthropogenic activities with several channel parameters for instance incisions, narrowing and migration [3]. These parameters are mainly resulted from disturbing the equilibrium of river dynamics and accelerate the rate of bank erosion. Human induced river bank erosion may become a natural disaster when people destroy natural species and settled within riparian zone, at least 100 m wide each side. [4] reported that narrower buffers provide habitat benefits for many species; however, protecting various riparian communities requires at least 100 m buffer zone. Many Geomorphologists have tended to examine the impact of human alterations on riverine environments [5,6,7] . Reference [8] concluded that researchers’ knowledge needed to be enriched that how human alters rivers. Numerous other researches have also made significant contribution on alteration of human activities in stream channels such as instream mining operations [9]; dam or bridge contractions [10,11]; channel restorations [12] and LULC (land use/cover) changes [13]. Reference [13] reported that anthropogenic activities have more superior impacts on river dynamics than natural events (Table 1). Human activities can cause drastic changes to fluvial geomorphic stability of stream channels as a geological agent, respect to leaving some fingerprints on the earth surfaces. In order to examine how human alterations historically impact stream channel, Remote Sensing (RS)