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Permitting Workshop Water Quality Control Division cdphe.state.co.us/wq Pueblo, Colorado May 18, 2005

2. Water Quality Permitting Perspective
Colorado Discharge Permit System (CDPS Permits)
What is a discharge permit?

3. The Permit It’s a legal document Do I have to have a permit limit?
Permit limits vs monitoring only
Past compliance and enforcement
Compliance schedules
Public Notice
Issuance
As with obtaining flow information, there are several sources of ambient water quality data and the data are not in the same form from these varying sources and it must be combined where appropriate, and manipulated to determine existing quality.
The general approach is to obtain as much data as possible and then determine which data are the most appropriate to use. Again, issues of older and more complete data sets versus more recent, less complete data sets must be evaluated. Also, issues of the form of the pollutant also arise. For example, the in-stream standards for many of the metals are often in the dissolved form but sometimes the only ambient water quality data may be in the total form. And, sometimes, the only data available is downstream data. Finally, sometimes there is no data available, anywhere. How to handle these issues is addressed when the WQCD determines existing quality.

4. Elements of Permitting
The Application
The Data
The Rationale
The Permit
Public Notice
Issuance
These are the basic steps involved in the development of the WQA and this presentation cover the basics and some of the nuances of each of these steps.
In previous years, the WQCD did not have an approach to ensure that each step (and each assumption) was documented. The Permits Unit and the Assessment Unit initiated a strategy two years ago to generate written WQAs that were well documented and were designed as an Appendix to attach to the permit rationale. This ensures that the WQAs can be more easily reproduced five years from now during the permit renewal cycle.
This year, the WQCD has developed a number of semi-automated permit writing tools to assist in the development of the WQA, as well as rationales and permits. The semi-automated permit writing tools to develop the WQA are currently in use and have almost halved the time required to develop each WQA. Additionally, the WQCD plans to soon begin utilizing the semi-automated permit writing tools to develop rationales and permits, particularly for the domestic dischargers.
Obviously, there are still unique instances where the semi-automated permit writing tools don’t fit all cases and therefore significant modifications must be incorporated. But, the WQCD is constantly improving their permit writing tools to address even the most unique circumstances and this is helping to stream-line the WQA development process.
In case they ask:
Spreadsheet Template: Plug in the water quality data and flow data, do some slight manipulations, and wallah, WQBELs and ADBELs are calculated automatically.
WQA Template: Each WQA is unique, but is developed using the WQCD’s boilerplate wording for each circumstance. A Data Source is completed for each facility’s discharge. The Data Source is then mail merged with the WQA Template. The output is a facility specific WQA. The tables from the Spreadsheet Template are then linked in. Then, any changes will be automatically transmitted to the facility-specific WQA.

5. The Application Gather your data Any new Parameters of Concern?
Facility Information
Facility description
Maps and figures
Discharge point(s)
Signatures
Generally, most of the receiving stream for existing facilities have been identified correctly. However, the WQCD occasionally finds that re-segmentation has resulted in changes that are not reflected in a facilities current permit. And, there are the cases where a facility has been identified as discharging to the incorrect segment.
A good map is paramount to the determination of the applicable in-stream standards. A map simply showing the location of the facility does not provide the necessary information about the exact discharge location of the facility in relation to the receiving stream.
The applicable standards of the receiving stream segment to which the facility discharges are not the only consideration, particularly if these standards are more lenient than downstream segment standards. This is illustrated in the case study that will be discussed shortly.
Wetlands determinations prescribed by the recent regulatory changes and definitions set out in Regulation 31 are going to have a profound impact on the application of standards to a facility. And this is going to have a significant impact on the resources expended in permitting by the WQCD in the years to come. It is currently the standard procedure of the WQCD to assume a zero dilution (zero low flow) within a wetlands when determining WQBELs, unless a mixing zone study has been completed to determine available dilution. However, based on the recent changes in regulatory definitions, the application of standards will also depend on the type of wetland.
For example, a wetland determined to tributary wetland will have standards applied based on those applied to the mainstem. Created wetlands, however, will be subject only to narrative standards and thus the downstream standard and the dilution of the mainstem will be used. Furthermore, there are often “All tributaries” segments that include wetlands and thus different in-stream standards may be applied.

6. The Rationale What’s a Rationale?
Computing low flows is not an easy process particularly when a flow record must be synthesized. Adjustments based on daily diversion flow records oftentimes result in negative, impossible flows. Sometime, the only available flow records are 20 or more years old.
Complicating the process is that not all flow data come in the same form so the flow data must be manipulated so that it can be input in to a model named DFLOW which then computes acute and chronic low flows. And, the DFLOW model is not Y2K compliant (or at least year 2000 data cannot be input as of yet). Thus, the WQCD currently has to change the dates on the year 2000 data before it can be input to DFLOW).
The WQCD’s general approach is to determine low flows based on a period of record reflecting the daily average flows over the most recent 10 year period. There are exceptions to this rule. For example, the Town of Alamosa is located in a valley that is subject to early spring and summer seasonal peaks and the flow record has no pattern from year to year. Because of the strange inconsistent pattern, it was more appropriate to evaluate the most recent 20 years when determining low flows. Another exception is when there is a limited period of record (e.g., only 3 years of recent data).
Sometimes, there is a year of recent data and numerous years of older data and then it is a challenge to determine which source of data to use. Or, downstream and upstream gages with equally difficult flow records to synthesize.
Once the “most appropriate” data are obtained, adjustments are made to the daily flow record where appropriate, DFLOW is run, and adjustments (such as the use of watershed ratios or subtraction of the facility contributions) are made, and the upstream low flows are computed.
Just as a reminder, the regulations prescribe the low flows that must be determined for each facility. These are the acute low flow (also known as the 1E3, the one-day low flow recurring over a three year period) and chronic low flow (a.k.a., the 30E3, a 30 day average low flow recurring in a three year period).

7. The Data The Water Quality Assessment Effluent Data Upstream Data
There are numerous data sources that the WQCD utilizes when attempting to determine low flows.

8. Questions?