Effects of Climate and Development on the Hydrology and Geomorphology of the Yellow Creek Watershed, Summit and Medina Counties, OH PDF Download

Author: Adam J. Delaney
Publisher:
ISBN:
Category : Floods
Languages : en
Pages : 235

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Book Description
The goal of this study was to determine the relative contributions of increased flood frequency and continued land development on geomorphic change and damage to infrastructure throughout the Yellow Creek, OH watershed. Comprised of five sub-watersheds, the Yellow Creek watershed is located in Northeast Ohio and is a tributary of the Cuyahoga River. In Northeast Ohio, a statistically significant change point in both heavy precipitation and stream flow occurred in July 2003. On the USGS Cuyahoga River Old Portage stream gage record, there were only 18 days of mean daily discharge above the top 1% flood category (76 m3s−1) during the 13 years prior to July 2003 compared to 79 days in the 13 years after July 2003. Land cover data reveals that impervious cover in the watershed has increased by 0.80% from 1985-1996, 0.32% from 1996-2001, 0.67% from 2001-2006, and 0.38% from 2006-2010. The five sub-watersheds have contrasting development histories and vary from 4.5% to 23.5% imperviousness. Water level loggers were installed to measure hydrograph variability between the five sub-watersheds. Water samples were also taken on 11/10/15, 2/3/16, and 2/24/16 in the five sub-watershed streams to find the effect development has on road salt concentration in the stream. Aerial photos for nine years between 1994 and 2015 were used to assess changes in stream geomorphology through time. Results show that geomorphic change has been greater after July 2003 compared to before July 2003. These post-2003 geomorphic changes include an increase in unvegetated mid-channel bars and point bars as well as amplified channel migration. Elsewhere, Yellow Creek shows straightening and widening in response to increased flooding events. The 2000 to 2005 and 2012 to 2015 photo intervals showed the largest geomorphic change throughout the Yellow Creek watershed, especially in areas with steep topography and stream slope. Although urbanization in the watershed results in increased runoff, since 2003 increased flood frequency has a larger effect on geomorphology change than increases in development. Upon analyzing data from water level loggers, results show that land cover, vegetative cover, soils, slope, precipitation intensity, and flood storage capacity all play an important role on hydrograph shape and time of peak discharge between the five sub-watershed streams. Sourek Run is the sub-watershed with the largest amount of impervious cover (23.5% as of 2010) and is the flashiest sub-watershed of the five and sensitive to small-scale precipitation events. The headwater, Upper Yellow Creek with less impervious cover (8.93% as of 2010) shows a generally round hydrograph and arrives later in time relative to other sub-watersheds likely due to its low slope, increased soil storage capacity and infiltration. Winter time snow melt and high magnitude summer time rainfall events created synchronous or near synchronous peak discharge time between the five sites. It also was found that road salt contamination was present in the Yellow Creek watershed during winter months, and the amount of development in the small sub-watershed areas (