Jordan Jurisdictional Allocation Model Development

You are encouraged to submit any comments on the model development process to NCDWQ and/or TJCOG using the following addresses.  Technical questions are best directed to DWQ, while contract or procedural comments can be sent to TJCOG. 

Rich Gannon,, DWQ Non-Point Source Planning Supervisor, 919-807-6440

Heather Saunders Benson,, TJCOG Senior Water Resources Planner, 919-558-9319 


Jordan Lake Allocation Model TJCOG Closing Contract Memorandum

Tetra Tech Modeling Documents


Technical Memorandum 3-Model Performance and Interpretation of Results for Jordan Model

Technical Memorandum 2-Summary of Model Configuration Prepared for Jordan Watershed Modeling

Technical Memorandum 1-Summary of Input Datasets for Jordan Watershed Modeling

BMP Approach Recommendation Memorandum

Jordan Allocation Model, Tetra Tech QAPP for Scope of Work

Jordan Allocation Model, Tetra Tech Scope of Work

Jordan Allocation Model, Tetra Tech Timeline of Work


Model Review Documents

TetraTech Presentation to NSAB; Proposed Scope of Work for Jordan Watershed Modeling-Phase 2

TetraTech Scope of Work for Jordan Watershed Modeling – Phase 2



Independent, Third-Party Reviews

319 Grant Sponsored Review; University of Virginia, Teresa Culver 

Dr. Glenn Fernandez, EPA Region 4 TMDL Modeling Expert

TetraTech Jordan Watershed Model:  Preliminary Response to Independent Reviewers' Comments


Stakeholder Reviews

NCDOT Sponsored Review; LimnoTech

TetraTech Jordan Watershed Model:  Preliminary Response to NCDOT Comments

City of Durham Review

TetraTech Jordan Watershed Model:  Preliminary Response to City of Durham Comments


RFQ and Project Timeline

Jordan Allocation Model, RFQ

Jordan Allocation Model, Timeline



TT Update to Full NSAB (Model Revisions), May 2, 2014, TT Presentation

TT UPdate to Full NSAB, November 8, 2013, TT Presentation

NSAB/TT/DWQ Subcommittee Meeting 5, October 23, 2013, TT Presentation

TT Update to Full NSAB, August 2, 2013, TT Presentation

NSAB/TT/DWQ Subcommittee Meeting 4, July 25, 2013, TT Presentation

TT Update to Full NSAB, May 13, 2013, TT Presentation

NSAB/TT/DWQ Subcommittee Meeting 3, April 24, 2013, Meeting Notes

NSAB/TT/DWQ Subcommittee Meeting 2, January 16, 2013, Meeting Notes

Regulated Entities Information Meeting, November 20th 2012, 10am to 12:30pm

Room 101, Koury Business Center, Elon University


DWQ Presentation on Existing Development Rule and NSAB

TetraTech Presentation on Model Process

TJCOG Presention on How Regulated Entities Can Follow Process


Data Request with Instructions

Data Request Description

RFMT Quick Start Guide

RFMT Sending Instructions



The Jordan Nutrient Strategy is a set of state regulations designed to reduce nutrient loading to B. Everett Jordan Reservoir to restore full designated uses to its waters.  The strategy consists of Rules 15A NCAC 2B .0262 - .0272 as augmented or replaced by subsequent Session Laws 2009-216 and 2009-484.  The session laws set requirements regarding existing developed lands, including a requirement for the Department of Environment and Natural Resources to assign nutrient load allocations for existing development to municipalities, counties, and state and federal entities that have jurisdiction in the Jordan Lake watershed.  Allocations are to reflect application of strategy percentage reduction goals to loads representative of the baseline period, 1997 through 2001, adjusted to account for loading increases post-baseline and prior to implementation of new development programs that are scheduled to commence September 2012.  Allocations are to be established in terms of annual mass loads delivered to Jordan Lake from these entities’ lands in each of three subwatersheds.


Allocations thus assigned to the parties subject to this regulation will effectively serve as benchmarks they will use, in combination with recognized load-reducing practices and associated load reduction estimation methods, to design load reduction programs.   The subject parties will use these programs, following approval by the NC Environmental Management Commission, to guide their implementation of nutrient load-reducing activities on a continuous basis toward the objective of meeting the allocations or until the lake’s water quality is recovered, whichever comes first. 


The session law establishes a Nutrient Scientific Advisory Board, or NSAB, and empowers it with the ability to recommend an appropriate method for estimating these allocations and the NSAB considers the development of a watershed model as necessary for establishing these allocations.  A nutrient loading model for Jordan Lake watershed was developed in 2003.  The NSAB has reviewed that modeling approach and concluded that it was not compatible with the current regulatory purpose because the model did not retain the ability to associate specific land cover data or related loading outputs with local or other government jurisdictional boundaries.  In addition they recognized certain features of the model that they felt would be important to improve upon given the current, different regulatory purpose.  Key features were: representation of onsite wastewater processes, which appear to overestimate this source; limited number of instream calibration points, believed to bias load estimates upward due to their proximal location downstream of wastewater discharges; and now-outdated delivery component coefficients.    


Given the intended use of the allocations as described above, another fundamental interest is to ensure that methods developed to estimate nutrient load reductions associated with management measures and applied towards the allocations are compatible with the model as used to set allocations, and that the model adequately provides for estimation of load reductions regarding those measures for which it is determined to be the most appropriate tool.   


The model is expected to be a “living model” that will undergo reruns and refinements in the future, and the Board and the Division want the product to be designed to accommodate future hypothesis testing, evaluation of alternative management scenarios, and reruns with updated land cover inputs as resources become available.  The model may be used in the future by technically trained members of the Division, its contractors, local governments, or researchers.  The model should be built to enable these future uses.  The Board and the Division will seek to ground these interests with the consultant before the modeling plan is finalized.



Timeline for Model Development