Lower Welland River Characterization Report - Niagara Peninsula ...

Lower Welland River Study Area
Characterization Report
Reach Characteristics:
The valley and channel lengths were measured and used to determine the valley and
channel slope, as well as channel sinuosity (the amount of bending in a stream).
Surficial geology and soil properties were identified.
Unstable valley side slopes were listed for those reaches that contained them.
The length of bank that contains a treed riparian buffer was measured and is listed as a
percentage of the total reach.
Historical Characteristics:
The present and historical land uses were determined for the watershed and along the
stream corridor. Any changes to the channel planform (the outline of an object when
viewed from directly overhead) as based on the 1934 aerial photographs were also
identified.
This data was collected for Thompsons Creek and the information can be found in the
Beaverdams and Shriners Creek Geomorphic Study, including Thompsons Creek report (NPCA
2010e).
Phase Two Data Collection
The second phase of the investigation required site visits in order to gather physical and hydraulic
information from site specific reaches within the watershed. The data collected during this phase
was based on the Vermont Stream Geomorphic Assessment Phase 2 and Phase 3 Handbook
(2005). Letters were mailed out to property owners living along the streams in the watershed and
site locations were based on landowner permission. The site characteristics collected from the field
were separated into five categories which are listed below.
Channel Bed and Planform Changes:
Identify whether or not riffle and steps were present.
The composition of the streambed and the average size of the largest particle were
identified. Pebble counts were completed at field sites that consisted of a mixture of
particle sizes and not just sand sized or smaller.
Bar types found along the bed were also identified.
The type and number of planform changes (i.e. flood chutes, neck cut-offs, channel
avulsions, and braiding) within the field site were listed.
Animal crossings along the field site were identified.
Valley and River Corridor:
Flow Modifiers:
Encroachments parallel to the stream (berms, roads, or paths) which may not allow
flood waters to overflow onto its floodplain were identified and measured.
The gradient and texture of adjacent terraces or hills was recorded.
It was noted whether or not the stream bank was continuous with the valley slope or
greater than one bankfull width away.
Grade controls were identified along the channel and their height was measured.
Channel constrictions present within the stream were noted.
51