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SBI Guidelines: Rivers and Streams

Introduction

The guidelines have been set against river structure, rather than species diversity.

Sites of Biological Importance

An SBI must consist of at least one primary feature (refer to the table below). If more than one primary feature is present and they are separated by less than 30 metres then the features should be combined into one SBI. If the river has one or more primary features and adjacent or nearby secondary features then all features are combined into one SBI. Where evidence exists of regular pollution incidents occur, sites should be excluded.

Site Boundary

  • 5 metre buffer zone either side of the banktop
  • Up and down stream boundaries- to the nearest feature e.g. bridge, field boundary or weir, etc.

Table 7: River features for Sites of Biological Importance

PRIMARY/ STAND ALONE FEATURES SIZE THRESHOLD
Eroding earth cliffs 1-1.5m high 20m stretch
Eroding earth cliffs 1.6m+ high 10m stretch
Braided channel Over 100m stretch
Unvegetated side bar (i.e. less than 50% vegetation) 10m+ in length
Unvegetated mid channel bar 10m+
River island 20m+
Natural waterfall None
Sedimentary deposits 20m+
Boulder cascade Over a 20m+ stretch
Riffle and pool/glide system. A riffle every 5-7 times the width of the channel
Woody debris 5 or more collections within 100m
Ox bow lake None
Any 4 "in combination feature" Within a 100m stretch
SECONDARY/ IN COMBINATION FEATURES SIZE THRESHOLD
Eroding earth cliffs Not meeting the size threshold set for Primary/stand alone features
Backwater None
Braided channel Less than a 100m stretch
Unvegetated side bar Less than 10m long
Unvegetated mid channel bar Less than 10m long
River island Less than 20m long
Botanically species rich buffer strip on the bank top ( to SBI Grade 2 standard) At least 2m wide
Sedimentary deposit Less than a 20m stretch
Boulder cascade Over less than a 20m stretch
Floating vegetation Abundant or dominant over a 50m stretch
Fringes of emergent vegetation Abundant or dominant over a 50m stretch
Mature bank side trees, including hollow trees and exposed root plates None
Woody debris Less than 5 collections within 100m
ADDITIONAL FEATURES (already covered separately in the Guidelines.)
Wetlands:
  • Reedbed
  • Fen
  • Wet Grassland
  • Wet woodland
  • Pond/lake/ditch
  • Marsh bog
Within 15m of river. These features can be encompassed within the SBI boundary if they are of sufficient quality.
Presence of SBAP and other key species in or adjacent to the river channel.  

These guidelines are currently (December 2017) under review and the working draft of the new guidelines is available here on the understanding these guidelines have not been ratified by the Local Sites Partnership.

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Version 6.01 (December 2017) Copyright © Staffordshire Wildlife Sites Partnership, 2018 Last Updated: 30/04/2015