Changes in stream temperatures in response to restoration of groundwater discharge and solar heating in a culverted, urban stream

Abstract

Changes in stream temperatures in response to restoration of groundwater discharge and solar heating in a culverted, urban stream A B S T R A C TBoone Creek is a mountainous headwater stream that lies within an urbanized environment in north-western North Carolina. The primary source of thermal pollution in Boone Creek is the urban infrastruc-ture, which affects stream temperatures through (1) heated runoff, which creates temperature surges and (2) the elimination of groundwater-surface water interactions. In this study, we use a Monte Carlo ther-mal mixing model to predict the thermal impact of removing a 700-m-long culvert. Our thermal mixing model balances stream discharge and temperatures with surface-heat exchange parameters and restored baseflow. We calculate the daily-average groundwater discharge velocity at 15 locations in the stream using signal decay in streambed temperatures, and utilize a Monte Carlo implementation of the hetero-geneous baseflow field in the thermal mixing model. We also calculate surface-heat exchange per unit area for conditions upstream and downstream of the existing culvert and utilize those values in the ther-mal mixing model. Our modeled temperatures suggest a decrease in summer stream temperatures down-stream of the culvert that average 1.35 ° C and 1.17 ° C for upstream and downstream surface-heat exchange conditions, respectively. The results of our study have implications for the balance between baseflow and the urban infrastructure in any high-gradient urban stream that experiences similar ther-mal effects.

Using subsurface temperatures to derive the spatial extent of the land use change effect

“…For example, Anderson et al (2010) examined the thermal impact of removing a culvert and the restoration of groundwater discharge on stream temperature in a highly urban setting in northwestern North Carolina. Rayne et al (2008) evaluated the effects of riparian forest harvesting on the maximum water temperatures in wetlandsourced headwater streams of British Columbia, Canada.…”

Urbanization influences on stream temperature behavior within low-discharge headwater streams

“…Boone Creek is a moderate-gradient urban stream that is influenced by high-gradient tributaries and is a tributary of the South Fork New River. The upper and lower reaches of the stream are separated by a 700 m culvert, effectively creating two streams within the study area (Anderson et al, 2010). While the majority of the study area experiences extensive urbanization, the upper segment has limited areas of riparian buffering and shading due to vegetation.…”

Comparing various artificial neural network types for water temperature prediction in rivers

“…However, the importance of such factors like discharge variations (Pekarova et al, 2008), flow regulations (Dickson et al, 2012), groundwater runoff contribution (Loinaz et al, 2013;MacDonald et al, 2014), mesoscale habitat types (Long and Jackson, 2014), urbanization (Anderson et al, 2010;Xin and Kinouchi, 2013), forest burning , ice cover (Caissie et al, 2014) or spillage of thermal pollutions (Vega et al, 1998;Kalinowska et al, 2012) highly depend on the site-specific conditions and cannot be easily generalized. This poses additional challenges for models describing relationship between meteorological conditions and streamwater temperatures.…”