The Effects of Road Crossings on Prairie Stream Habitat and Function

Abstract

Improperly designed stream crossing structures may alter the form and function of stream ecosystems and habitat and prohibit the movement of aquatic organisms. Stream sections adjoining five concrete box culverts, five low-water crossings (concrete slabs vented by one or multiple culverts), and two large, single corrugated culvert vehicle crossings in eastern Kansas streams were compared to reference reaches using a geomorphologic survey and stream classification. Stream reaches were also compared upstream and downstream of crossings, and crossing measurements were used to determine which crossing design best mimicked the natural dimensions of the adjoining stream. Four of five low-water crossings, three of five box culverts, and one of two large, single corrugated pipe culverts changed classification from upstream to downstream of the crossings. Mean riffle spacing upstream a t low-water crossings (8.6 bankfull widths) was double that of downstream reaches (mean 4.4 bankfull widths) but was similar upstream and downstream of box and corrugated pipe culverts. There also appeared to be greater deposition of fine sediments directly upstream of these designs. Box and corrugated culverts were more similar to natural streams than low-water crossings a t transporting water, sediments, and debris during bankfull flows.

The effects of road crossings on stream macro-invertebrate diversity

“…Habitat alteration is probably the greatest anthropogenic threat to freshwater ecosystems (Ogren and Huckins 2015). Our results are in line with previous studies stating that road crossings cause changes in stream channel geomorphology, and thus modify the natural stream bed habitat (Bouska et al 2010;Roy and Sahu 2018). The most obvious explanation for the difference among habitats at road crossings and the unaltered downstream and upstream sections is the use of concrete stream bed, as well as riprap with gabion (woven wire mesh unit filled with stones) at road crossings.…”

“…The riverbed at road crossings is frequently constructed of concrete and riprap, and this artificial surface is covered mostly by deposited silt and sand. All of these factors may reduce habitat heterogeneity at road crossings (Wellman et al 2000;Bouska et al 2010). Finally, road crossings can be potential barriers to the movement of fish and other aquatic organisms (Maitland et al 2016).…”

Evaluating the Effects of Culvert Designs on Ecosystem Processes in Northern Wisconsin Streams

“…The main motivation for culvert replacements is that improperly designed culverts can act as semipermeable or complete barriers to aquatic organism movement (Bouska and Paukert, ; Warren and Pardew, ), and that sedimentation, erosion and flood risk can exceed natural levels because of hydrologic changes through culverts (Bouska et al ., ; Gillespie et al ., ; Wellman et al ., ). Sometimes, these issues within culverts can transmit upstream or downstream to change stream geomorphology or hydrology in ways that could influence ecosystem processes over many metres or kilometres (Lachance et al ., ).…”

“…Culverts can also alter geomorphic characteristics within, upstream and downstream of the structures. Culverts that obstruct natural flow conditions can retain fine sediments during high discharge events, increase accumulation of fine sediments downstream or upstream of culverts (Bouska et al ., ; Lachance et al ., ; Wellman et al ., ) and influence the organic matter content of sediments upstream of culverts (Lachance et al ., ). For example, some box‐type culverts in Kansas have deeper mean bankfull depths and smaller width‐to‐depth ratios compared with natural stream channels, and riffle spacing is closer in stream reaches downstream of these culverts relative to those upstream (Bouska et al ., ).…”

Low-Water Crossings: An Overview of Designs Implemented along Rural, Low-Volume Roads

“…[15]. Studies have shown that stream crossings may change the form and function of stream ecosystem and habitat significantly and affect aquatic organism movement [16][17][18]. Warren Jr & Pardew [19] looked into movement of fish for 21 different species in seven families through the culvert, slab, open-box, and ford crossings and through natural reaches and found that overall fish movement was an order of magnitude lower through culverts than through other crossings or natural reaches.…”