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Delaware Comprehensive Assessment Procedure (DECAP) v5.2

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Developer

 Delaware Department of Natural Resources and Environmental Control

Latest documentation

 2009

Designed for use in
Delaware, USA

Ongoing

 Yes

Assessment purpose

 Condition, Processes and components, Values/Services

Assessment criteria

 Physical and chemical, Management and planning, Flora

Method type

 Field

Timescale

 Medium term – The timescale for this method may vary depending on the spatial scale of the assessment. This is a comprehensive method, which is ideally suited to assess multiple sites and HGM types within a broader watershed.

Scale

 Site/habitat

Wetland system

 Lacustrine, Palustrine, Riverine

Description and method logic

Method purpose

The intended use of the Delaware Comprehensive assessment Procedure (DECAP) is to collect data that can be used to assess the condition of wetlands in relation to minimally disturbed sites.

Summary

The Delaware Comprehensive Assessment Procedure (DECAP) v5.2 is a comprehensive assessment methodology used to evaluate the condition of non-tidal wetlands in the Coastal Plain of Delaware and Maryland. The DECAP includes provision for classification of wetland hydrogeomorphic (HGM) subclass: riverine; depressional; or flat.

Method logic

Pre-field tasks involved in DECAP are as follows:
1.Determine wetland dimensions
2.If riverine, determine wetland stream order
3.Determine XY coordinates for buffer plots
4.Landowner liaison
5.Collate field maps.

The DECAP assessment area is defined depending on the Hydrogeomorphic (HGM) type being assessed. Riverine, flat and depressional wetlands follow different procedures for selecting assessment areas. Vegetation assessment plots are located within the centre of assessment areas, and their specific location is ideally determined by using a probabilistic sampling design.

DECAP assesses vegetation, geomorphology and hydrology for each assessment area. The datasheets provided by DECAP are as follows:
1.Tree and sapling datasheet
2.Shrubs and vines datasheet
3.Understorey plot datasheet
4.Snags/large downed wood datasheet
5.Microtopography/soil/sphagnum
6.Non-riverine hydrology datasheet OR
Riverine Hydrology datasheet AND
Riverine morphology datasheet
7.Buffer overstory datasheet
8.Site information datasheet.

Following the field assessment, a qualitative disturbance rating is determined from the observations of stressors and alterations to vegetation, wetland hydrology, land use and soils. Best professional judgement is used to assign the site a numerical Qualitative Disturbance Rating from least disturbed (1) to highly disturbed (6) relative to other sites within the watershed.

DECAP variables are synthesised in order to apply the Index Wetland Condition (IWC) and produce a wetland condition score. Results from DECAP assessment are converted into Functional Condition Indices (FCIs), which incorporate metrics based on their degree of impact on wetland condition in regards to a reference state. The FCIs are: a) buffer integrity; b) wildlife habitat integrity; c) plant community integrity; d) hydrologic flux and storage; and e) biogeochemical cycling. Each HGM class incorporates a different suite of metrics for calculating each FCI. The formulae for calculation of the  IWC are also dependent on HGM class. The IWC produces a score out of 100.

Wetland condition categories are based on IWC score distributions within a defined region e.g. a watershed. For example, the condition categories for the Nanticoke Wetlands are based on breakpoints at the 25th and 75th percentile of IWC results, creating three categories: a) highly stressed; b) moderately stressed; and c) minimally or not stressed.

Criteria groupings of the method

The assessment criteria for DECAP are comprehensive, covering flora, physical and site/management attributes.

Data required

  • Vegetation plot survey
  • Tree measurements
  • Other vegetation measurements
  • Hydrology observations
  • Soil indicators
  • Microtopology observations
  • HGM type and classification
  • Land use information.

Resources required

Expertise required

DECAP should be completed by practitioners who have completed a training course on how to properly perform the method. Experience and/or education in wetland classification and assessment, and native flora and soil properties is desired.

Materials required

Access to supporting maps and information and land access. General survey equipment is required, as well as provisions for measuring vegetation, soil and hydrology attributes.

Method outputs

Outputs

  • Completed datasheets
  • Qualitative disturbance rating
  • FCI scores
  • IWC score
  • Wetland condition category rating.

Uses

  • Wetland assessment and management
  • Watershed management
  • Decision support
  • Impact assessment.

Criteria by category

    Physical and chemical

    • Non-riverine hydrology
      • Depth of mapped ditches
      • Location of ditches (if no GIS information avail)
    • Riverine hydrology
      • Inside assessment area stream condition
      • Outside assessment area stream condition
    • Riverine morphology
      • Bank elevation
      • Deepest point in channel
      • Top-of-bank height
    • Soils
      • Drainage class
      • Hydric indicators
      • Presence and depth of O and A horizon
      • Sphagnum habitat and moisture regime

    Management and planning

    • Land use
      • Buffer land use
      • Forested buffer types
    • Site information
      • Filling
      • Hydrologic disturbance
      • Microtopography disturbance
      • Natural hydrology sources for depressions
      • Vegetation disturbance
      • Wetland vegetation zone cover

    Flora

    • Buffer overstory
      • Tree height/diameter
    • Microtopography
      • Hummock and tip-up presence (tree root depressions- upturned tree
    • Shrubs and vines
      • Blackberry presence
      • Shrub species/stem count
      • Vine species
    • Snags and large downed wood
      • Large downed wood and coarse woody debris
      • Snag height/diameter
    • Trees and saplings
      • Sapling species/height/diameter
      • Tree species/height/diameter
    • Understorey
      • Additional understorey species
      • Understorey species

Review

Recommended user

Potential users of the DECAP (or of the information generated by its use) include field staff and managers.

Others who might be interested in using the outputs from DECAP include researchers and staff from science-based non-governmental organisations, and environmental and advocacy groups. Consulting firms, educators, academic researchers, and reporters for written and broadcast media, along with the general public, will also find results from the DECAP to be useful to their interests in wetland science and management. This technique is recommended for government agencies involved in regional wetland monitoring. Land managers and NRM practitioners may find this methodology useful as it is a broadly applicable rapid assessment of wetland condition.

Strengths

  • Comprehensive assessment
  • Field-based measurements
  • Complements DERAP for broadscale assessments.

Limitations

  • High level expertise required to implement method including training requirements.
  • No scoring procedure for individual wetlands, is comparative.
  • Does not include fauna.

Case studies

Christina

DECAP: Broadkill Watershed

Rogerson, AB, Jennette, MA & Howard, AM (2013), Condition of wetlands in the Broadkill River Watershed, Delaware.. [online], Delaware Department of Natural Resources and Environmental Control, Watershed Assessment and Management Section, Dover, DE.. Available at: https://dnrec.alpha.delaware.gov/watershed-stewardship/wetlands/assessments/broadkill/http://www.dnrec.delaware.gov/.

DECAP: Inland Bays Watershed

Jacobs, A, Rogerson, A, Fillis, D & Bason, C (2009), Wetland condition of the Inland Bays watershed. Volume 1. Delaware. [online], Department of Natural Resources and Environmental Control, Watershed Assessment Section, Dover, DE.. Available at: https://dnrec.alpha.delaware.gov/watershed-stewardship/wetlands/assessments/inland-bays/.

DECAP: Murderkill Watershed

Rogerson, AB, Jacobs, AD & Howard, AM (2011), Wetland condition for the Murderkill River Watershed, Delaware. [online], Delaware Department of Natural Resources and Environmental Control, Watershed Assessment Section, Dover, DE.. Available at: https://dnrec.alpha.delaware.gov/watershed-stewardship/wetlands/assessments/murderkill/.

DECAP: Nanticoke River Watershed

Jacobs, AD & Bliel, DF (2008), Condition of nontidal wetlands in the Nanticoke River Watershed, Maryland and Delaware.. [online], Delaware Department of Natural Resources and Environmental Control, Watershed Assessment Section, Dover, DE.. Available at: https://dnrec.alpha.delaware.gov/watershed-stewardship/wetlands/assessments/nanticoke/.

DECAP: St. Jones Watershed

Rogerson, AB, Jacobs, AD & Howard, AM (2010), Wetland condition of the St. Jones River Watershed.. [online], Delaware Department of Natural Resources and Environmental Control, Watershed Assessment Section, Dover, DE.. Available at: https://dnrec.alpha.delaware.gov/watershed-stewardship/wetlands/assessments/st-jones/.

Leipsic

Mispillion

Smyrna

Links

References

  1. Jacobs, AD, Whigham, DF, Fillis, D, Rehm, E & Howard, A (2009), Delaware Comprehensive Assessment Procedure Version 5.2.. [online], Delaware Department of Natural Resources and Environmental Control, Dover, DE.. Available at: http://www.dnrec.delaware.gov/Admin/DelawareWetlands/Documents/DECAP%20Protocol%20v5.2%20July%2009.pdf.

Last updated: 7 February 2019

This page should be cited as:

Department of Environment, Science and Innovation, Queensland (2019) Delaware Comprehensive Assessment Procedure (DECAP) v5.2, WetlandInfo website, accessed 30 August 2024. Available at: https://wetlandinfo.des.qld.gov.au/wetlands/resources/tools/assessment-search-tool/delaware-comprehensive-assessment-procedure-decap-v5-2/

Queensland Government
WetlandInfo   —   Department of Environment, Science and Innovation