2021 Binghamton Conference

Private Practices Degrading Public Streams: History and Impacts of Channelization and Levee Construction in Big Barren Creek Watershed, Mark Twain National Forest, Missouri

First place poster presentation winner
  • Hannah Alkier, Katie Grong 
  • Faculty Advisor: Dr. Tasnuba Jerin and Dr. Robert T. Pavlowsky
  • Poster [.pdf]

The impacts of agricultural channelization and subsequent head-cut development on the geomorphic transformation of stream channels and network patterns are poorly understood on the Ozark Highlands. In the Big Barren creek (BBC) watershed, channelization is a prevalent land use practice for flood management as well as an attempt to control erosion, improve drainage, and create a straighter channel. This human disturbance, through levee construction and gravel mining, modifies the balance of available and transported sediment causing channel instability. While channelization widens and deepens stream beds with the goal of containing flood events within the channel, it can degrade a healthy riparian vegetation zone and increase the risk of damaging floods. This study aims to assess the history of channelization, headcut locations, and channel form changes to better understand the geomorphic processes and disturbance trajectories in BBC. A LiDAR DEM was used to map the locations and distribution of channelized and head-cut channels. Further, channel morphology and bed material surveys were performed at several head-cut sites to identify the characteristics and consequences associated with their formation and extension upstream. Channelization became a common practice beginning by the 1950s with some new projects
occurring after 2000. Landowners excavate the entire channel length on private property with upstream head-cutting and downstream sediment pulses extending onto adjacent public lands. On-going maintenance efforts including ad hoc bank stabilization and gravel mining practices unintentionally reactivate channel erosion to continue the disturbance cycle. Historical channel development by human action illustrates the role of historical contingency in geomorphic evolution in BBC.

 

Geomorphic Patterns of Riparian Tree Mortality and Recovery After a 500-Year Flood Event on an Ozark Highlands River

  • Joshua Hess, Joseph Nash
  • Faculty Advisor: Dr. Robert T. Pavlowsky
  • Poster [.pdf]

Climate change has increased the frequency of large floods in rivers draining in the Ozark Highlands resulting in higher rates of channel sedimentation, bank erosion, and damage to infrastructure. However, the effects of flood events on riparian forests in the Ozark Highlands
are not well understood. This study assesses the effects of a large flood (> 500 year recurrence interval) during April May 2017 on riparian forests on the North Fork of the White River, Missouri. Two post flood (August 2017 and March August 2021) field surveys were conducted to assess patterns of riparian forest damage, mortality, and recovery. Initial post flood riparian tree mortality was 43% of 511 trees surveyed. Repeat surveys in 2021 showed mortality increased to 79%. Additionally, patterns in canopy cover and forest damage were examined spatially and temporally through ArcGIS and aerial imagery. Post flood canopy cover was reduced to 17% of the pre flood extent, increasing to 37% in 2020. Damage patterns are related to landform with recovery rates increasing downstream from head to tail of a large bar floodplain complex. This information can be used to understand ecological disturbance by floods and to improve management practices in Mark Twain National Forest.

 

Spatial and Temporal Variations in Beach Erosion Rates Along Treasure Beach, South Coast of Jamaica

  • Elande’ Engelbrecht
  • Faculty Advisor: Dr. Robert T. Pavlowsky
  • Poster [.pdf]

Anthropogenic climate change is causing sea level rise and shoreline changes that threaten the environment and economy of coastal communities in Caribbean Island nations. To assess this risk, this study quantifies shoreline changes at Treasure Beach in St. Elizabeth Parish on the south coast of Jamaica since Hurricane Ivan in September 2004. Over 11 km of shoreline are assessed with about half being sandy beaches ranging from <100 to 700 m in length with the remainder lined by rock headlands and beach rock outcrops. Multiple years of aerial photographs and satellite imagery are used along with field profiles to evaluate beach erosion and deposition trends at the seasonal, storm event, and decadal scales. Preliminary results indicated that beach widths vary annually and over 5-10 year periods. Shoreline changes along Treasure Beach at 50 m intervals averaged -0.5 m/yr (erosion) from 2013 to 2016. Maximum erosion rates of -5 m/yr were observed with maximum deposition rates of 2 m/yr. Both sand deposition and erosion occurred during storm events. However, by 2016 only about 40% of the sand beach length had recovered to its original location prior to Hurricane Ivan in 2004.

 

Long-Term Impact of Exploitative Logging on Forest Watershed Hydrology in the Missouri Ozarks

  • Marc R. Owen, Shoukat Ahmed, Sierra N. Casagrand
  • Faculty Advisor: Dr. Robert T. Pavlowsky
  • Poster [.pdf]

It is well known that stream channels adjust to human-induced landscape disturbance by
expanding to accommodate increases in runoff. Headwater stream channels in the Ozarks show signs of instability as bank erosion, incision, and bed aggradation are common even in watersheds that are mostly forested. This study explores the idea that stream channels are adjusting to the reduction in shortleaf pines in the region contributing to increased runoff in the winter and early spring. Shortleaf pines intercept 3x more rainfall than bare deciduous tree and runoff is slowed by decreasing throughfall and stem flow rates. Implications are that climate change could exacerbate instability as the number of high intense rainfall events is increasing in southeast Missouri.