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Delaware Rapid Assessment Procedure (DERAP) v6.0

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Delaware Department of Natural Resources and Environmental Control

Latest documentation


Designed for use in

Delaware, USA



Assessment purpose

Condition, Processes and components

Assessment criteria

Physical and chemical, Management and planning, Flora

Method type

Field, desktop


Short term – DERAP is a rapid assessment procedure, and should take 2 people no more than 1 hour per site.


Landscape/Catchment, Site/habitat

Wetland system

Lacustrine, Palustrine, Riverine

Description and method logic

Method purpose

The DERAP is designed to be a rapid field assessment of wetland condition at a wetland site. It is designed for any type of wetland, results in a single score of condition, and can be validated with the Delaware Comprehensive Assessment Procedure (DECAP). Scoring produces one overall score of condition  developed through a process of calibrating the presence of stressors at a site to comprehensive wetland condition data using the DECAP Index of Wetland Condition (IWC).


The Delaware Rapid Assessment Procedure (DERAP) v6.0 is a rapid assessment method designed for assessing the condition of all non-tidal wetlands in the Outer Coastal Plain regions of Delaware and Maryland, USA. This method is designed as a rapid field site assessment and can be used in conjunction with the Delaware Comprehensive Assessment Procedure (DECAP).

Method logic

DERAP contains provisions for classification and assessment. The desktop component of DERAP largely takes place during the pre-visit site evaluation. The DERAP procedure is as follows:
1.Determine stream order (for riverine assessment)
2.Landowner permissions
3.Print and review maps
4.Classify the wetland for assessment
5.Define assessment area using random probabilistic sampling design
6.Conduct field assessment
7.Compute final DERAP scores using assessment procedures
8.Determine a condition class from DERAP score.

A Qualitative Disturbance Rating (QDR) is assigned to the assessment area by the entire field crew upon the assessment completion. The QDR is rated from 1-6, categorised as:
  • Minimal Disturbance Category (QDR 1-2)
  • Moderate Disturbance Category (QDR 3-4)
  • High Disturbance Category (QDR 5-6)

DERAP rates assessment areas using weighted scoring dependant on the hydrogeomorphic (HGM) class and sub-class of the wetland. These weights were determined through refinement of DECAP index measures. Condition classes based on the DERAP total score:
  • For Flats: Minimally or Not Stressed (≥88); Moderately Stressed (<88 and ≥80.5; <08.5 and ≥65); Severely stressed (<65 and ≥57.5; <57.5)
  • For Riverine: Minimally or Not Stressed (≥85); Moderately Stressed (<85 and ≥75.5; <75.5 and ≥47); Severely stressed (<47 and ≥37.5; <37.5)
  • For Depression: Minimally or Not Stressed (≥73); Moderately Stressed (<73 and ≥57; <57 and ≥53); Severely stressed (<53 and ≥37; <37).

For reporting purposes breakpoints are determined from scores QDR ratings of over 200 sites. Sites in the 25th percentile DERAP score with a QDR of 1 or 2 are rated as minimally or not stressed. Sites in the 75th percentile DERAP score with a QDR of 5 or 6 are rated as severely stressed. All other scores can be defined as moderately stressed.

Criteria groupings of the method

The assessment criteria for DERAP are based on measures of stressors to wetland condition.

Data required

This methodology requires the collection of limited background data, including thematic maps, aerial photographs and information specific to each assessment area. The assessment is primarily qualitative.

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. It usually requires a two person team.

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


The DERAP can produce the following outputs:
  • DERAP score and condition rating
  • Qualitative Disturbance Rating (1-6): minimal, moderate and high
  • Reporting score using DERAP score and QDR.


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

Criteria by category

    Physical and chemical

    • Buffer stressors
      • Channelised streams or ditches
      • Roads
    • Habitat stressors
      • Dense algal mats
      • Elevated road
      • Non-elevated road
      • Paved road
    • Hydrologic stressors
      • Alterations (weir/dam/road)
      • Ditches
      • Filling and/or excavation
      • Flooding
      • Microtopographic alterations
      • Soil subsidence/root exposure
      • Stormwater and point sources
      • Stream alteration (riverine)

    Management and planning

    • Buffer stressors
      • Development
      • Forest harvesting within 15 years
      • Golf course
      • Landfill/waste disposal
      • Mowed area
      • Poultry and livestock operation
      • Row crops, nursery plants, orchards
      • Sand/gravel operation
    • Habitat stressors
      • Chemical defoliation
      • Harvesting within 50 years
      • Pine plantation conversion
      • Vegetation mowing, farming, grazing, recovery


    • Habitat stressors
      • % of assessment area forested
      • Basal area factor BAF (10) of Dominant Forest Cover (comprehensive assessment)
      • Dominant forest age
      • Excessive herbivory
      • Presence of invasive species
      • Presence of nutrient indicator species (depressional wetlands)


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.


  • Rapid field assessment
  • Consistent with comprehensive assessment procedures (DECAP).
  • Disturbance and condition ratings.


  • Qualitative measures
  • Limited backgrounding and desktop assessment
  • requires DECAP to have been undertaken before it can be used
  • High level expertise required to implement method including training requirements
  • Does not include fauna.

Case studies

(not documented)



  1. Jacobs, AD (2010), Delaware Rapid Assessment Procedure Version 6.0.. [online], Delaware Department of Natural Resources and Environmental Control, Dover. Available at:

Last updated: 7 February 2019

This page should be cited as:

Department of Environment and Science, Queensland (2019) Delaware Rapid Assessment Procedure (DERAP) v6.0, WetlandInfo website, accessed 27 October 2023. Available at:

Queensland Government
WetlandInfo   —   Department of Environment and Science