Evaluating Concentrated Flowpaths in Riparian Forest Buffer Contributing Areas Using LiDAR Imagery and Topographic Metrics

Riparian forest (CP22) buffers are implemented in the Chesapeake Bay Watershed to trap pollutants in surface runoff thus minimizing the amount of pollutants entering the stream network. For these buffers to function effectively, overland flow must enter the riparian zones as dispersed sheet flow to facilitate slowing, filtering, and infiltrating of surface runoff. The occurrence of concentrated flowpaths, however, is prevalent across the watershed. Concentrated flowpaths limit buffer filtration capacity by channeling overland flow through or around buffers. In this study, two topographic metrics (topographic openness and flow accumulation) were used to evaluate the occurrence of concentrated flowpaths and to derive effective CP22 contributing areas in four Long-Term Agroecosystem Research (LTAR) watersheds within the Chesapeake Bay Watershed. The study watersheds include the Tuckahoe Creek watershed (TCW) located in Maryland, and the Spring Creek (SCW), Conewago Creek (CCW) and Mahantango Creek (MCW) watersheds located in Pennsylvania. Topographic openness identified detailed topographic variation and critical source areas in the lower relief areas while flow accumulation was better at identifying concentrated flowpaths in higher relief areas. Results also indicated that concentrated flowpaths are prevalent across all four watersheds, reducing CP22 effective contributing areas by 78% in the TCW, 54% in the SCW, 38% in the CCW and 22% in the MCW. Thus, to improve surface water quality within the Chesapeake Bay Watershed, the implementation of riparian forest buffers should be done in such a way as to mitigate the effects of concentrated flowpaths that continue to short-circuit these buffers.

[1]  E. I. Bauereis.  Chesapeake Experience: NPS Chesapeake Challenge for Sustainable Development , 1992 .

[2]  Andrew K. Leight,et al.  An assessment of benthic condition in several small watersheds of the Chesapeake Bay, USA , 2011, Environmental monitoring and assessment.

[3]  Megan W. Lang,et al.  Lidar intensity for improved detection of inundation below the forest canopy , 2009, Wetlands.

[4]  R. Hirsch,et al.  Weighted Regressions on Time, Discharge, and Season (WRTDS), with an Application to Chesapeake Bay River Inputs , 2010, Journal of the American Water Resources Association.

[5]  James N. Galloway,et al.  Sources of nitrogen in wet deposition to the Chesapeake Bay region , 1998 .

[6]  Matthew J. Helmers,et al.  Assessment of concentrated flow through riparian buffers , 2002 .

[7]  Mary C. Watzin,et al.  Identifying and controlling critical sources of farm phosphorus imbalances for Vermont dairy farms , 2011 .

[8]  Minghua Zhang,et al.  Major factors influencing the efficacy of vegetated buffers on sediment trapping: a review and analysis. , 2008, Journal of environmental quality.

[9]  Bernhard Höfle,et al.  Historic Low Wall Detection via Topographic Parameter Images Derived from Fine-Resolution DEM , 2017, ISPRS Int. J. Geo Inf..

[10]  L. Linker,et al.  The Chesapeake Bay story: The science behind the program , 1995 .

[11]  P. Mayer,et al.  Meta-analysis of nitrogen removal in riparian buffers. , 2007, Journal of environmental quality.

[12]  Saied Mostaghimi,et al.  BMP impacts on sediment and nutrient yields from an agricultural watershed in the coastal plain region , 2001 .

[13]  Gregory W. McCarty,et al.  Topographic and physicochemical controls on soil denitrification in prior converted croplands located on the Delmarva Peninsula, USA , 2018 .

[14]  Thomas M. Isenhart,et al.  Sediment and nutrient removal in an established multi-species riparian buffer. , 2003 .

[15]  J. Hamlett,et al.  Integrated watershed- and farm-scale modeling framework for targeting critical source areas while maintaining farm economic viability. , 2013, Journal of environmental management.

[16]  Sarah C. Goslee,et al.  Topographic placement of management practices in riparian zones to reduce water quality impacts from pastures , 2012, Landscape Ecology.

[17]  Saied Mostaghimi,et al.  Vegetative Filter Strips for Agricultural Nonpoint Source Pollution Control , 1989 .

[18]  M. Shirasawa,et al.  Visualizing topography by openness: A new application of image processing to digital elevation models , 2002 .

[19]  R. W. Skaggs,et al.  Drainage Control to Diminish Nitrate Loss from Agricultural Fields 1 , 1979 .

[20]  In-Young Yeo,et al.  Topographic Metrics for Improved Mapping of Forested Wetlands , 2013, Wetlands.

[21]  Megan W. Lang,et al.  Water quality and conservation practice effects in the Choptank River watershed , 2008, Journal of Soil and Water Conservation.

[22]  Robert F. Carline,et al.  Responses to Riparian Restoration in the Spring Creek Watershed, Central Pennsylvania , 2007 .

[23]  Steven K. Mickelson,et al.  Multispecies riparian buffers trap sediment and nutrients during rainfall simulations. , 2000 .

[24]  D. Weller,et al.  Nutrient Interception by a Riparian Forest Receiving Inputs from Adjacent Cropland , 1993 .

[25]  Juan Carlos Fernandez Diaz,et al.  Archaeological Application of Airborne LiDAR with Object-Based Vegetation Classification and Visualization Techniques at the Lowland Maya Site of Ceibal, Guatemala , 2017, Remote. Sens..

[26]  Oky Dicky Ardiansyah Prima,et al.  Characterization of volcanic geomorphology and geology by slope and topographic openness , 2010 .

[27]  R. Yokoyama,et al.  Supervised landform classification of Northeast Honshu from DEM-derived thematic maps , 2006 .

[28]  Ross B. Leidy,et al.  Chemical movement in relation to tillage system and simulated rainfall intensity , 1995 .

[29]  Bernard A. Engel,et al.  Quantifying the effects of conservation practice implementation on predicted runoff and chemical losses under climate change. , 2017 .

[30]  Douglas L. Karlen,et al.  Topographic metric predictions of soil redistribution and organic carbon in Iowa cropland fields , 2018 .

[31]  D. Tarboton.  A new method for the determination of flow directions and upslope areas in grid digital elevation models , 1997 .

[32]  Ray B. Bryant,et al.  U.S. Department of Agriculture Agricultural Research Service Mahantango Creek Watershed, Pennsylvania, United States: Physiography and history , 2011 .

[33]  Garey A Fox,et al.  Comment on "major factors influencing the efficacy of vegetated buffers on sediment trapping: a review and analysis," by Xingmei Liu, Xuyang Zhang, and Minghua Zhang in the journal of environmental quality 2008 37:1667-1674. , 2009, Journal of environmental quality.

[34]  J. W. Gilliam,et al.  Sediment and Chemical Load Reduction by Grass and Riparian Filters , 1996 .

[35]  J. Newbold,et al.  Water Quality Functions of Riparian Forest Buffers in Chesapeake Bay Watersheds , 1997, Environmental management.

[36]  Thomas M. Isenhart,et al.  Ability of Remnant Riparian Forests, With and Without Grass Filters, to Buffer Concentrated Surface Runoff 1 , 2010 .

[37]  Gregory W. McCarty,et al.  Variations in Base‐Flow Nitrate Flux in a First‐Order Stream and Riparian Zone 1 , 2008 .

[38]  G. Oertel,et al.  Seismic stratigraphy and coastal drainage patterns in the Quaternary section of the southern Delmarva Peninsula, Virginia, USA , 1992 .

[39]  Caspar J. M. Hewett,et al.  Modelling and managing critical source areas of diffuse pollution from agricultural land using flow connectivity simulation , 2005 .

[40]  Gregory W. McCarty,et al.  Hydrology of a first-order riparian zone and stream, mid-Atlantic coastal plain, Maryland , 2005 .

[41]  P. J. Edwards,et al.  Forest Service-- National AgroforestryCenter 1-1-2012 Concentrated Flow Paths in Riparian Buffer Zones of Southern Illinois , 2013 .

[42]  J. Lyons,et al.  GRASS VERSUS TREES: MANAGING RIPARIAN AREAS TO BENEFIT STREAMS OF CENTRAL NORTH AMERICA 1 , 2000 .

[43]  David D. Bosch,et al.  Management effects on runoff and sediment transport in riparian forest buffers , 1999 .