The Arid West Water Quality Research Project

1997 Conference

April 23-25, 1997

(Selected Conference Materials)

Biological Criteria/Ecosystems Discussion Group

Biological Criteria
by Richard D. Meyerhoff, Ph.D.

Introduction

With considerable population growth in the arid West, the need for finding places to discharge wastewater is increasing. Traditionally, these discharges have been made to ephemeral streams and riverbeds resulting in the creation of effluent-dependent aquatic systems. Over time, these aquatic systems develop riparian communities that provide diverse habitat and food resources for wildlife.

Because no opportunity for in-stream dilution exists, point source discharges to ephemeral or effluent-dependent streams often have to meet water quality criteria at the "end-of-the-pipe". The cost of treatment for some pollutants can be high if there is no opportunity to allow the development of a mixing zone in a receiving waterbody. As populations grow, water resources become more limited and therefore have an increased economic value. As a result dischargers are increasingly looking for ways to reuse water rather than have to meet water quality criteria at the end-of-the-pipe.

From an economic perspective it makes more sense to reuse water than it does to pay for costly upgrades to wastewater treatment plants. However, if the discharge has created an aquatic ecosystem, then the loss of the discharge results in the loss of a potentially critical aquatic resource for wildlife. Given the limited natural aquatic resources currently available in arid regions, the loss of this aquatic ecosystem while making economic sense, makes little ecological sense.

Currently, the basis for decisions about the costs of treatment must be made on the chemical water quality criteria that have been applied to ephemeral and effluent-dependent streams. These criteria may or may not be appropriate as the data generated to develop these criteria may have not considered characteristics of water in the arid West, e.g., hardness or salinity, or appropriate aquatic species. Possibly more important than the chemical criteria, is the need to determine what it is that should be protected and what level of protection is necessary to achieve that goal.

Biological Group Meeting Notes

Session 1: Discussion of Biological Criteria Issues

The application of biological criteria to arid streams, particularly effluent-dependent streams of the arid West, was the subject of this first breakout session. The session was moderated by Dr. Richard Meyerhoff, Supervisor of the Water Quality Assessment Unit for the Arizona Department of Environmental Quality. Commencing with the list of proposed research topics provided to conference attendees, the participants in Biological Session 1 focused on modifying the Critical Candidate Issues lists (Pages 7 B 10 of this document) to eliminate issues the group felt were less critical and add others that were more pertinent to the problem as well as refine issue descriptions.

Chemical Criteria and Standards

• Develop criteria for species in ephemeral and effluent-dependent streams in the arid West.
• Develop chemical criteria for certain indicator species - for example, how salinity affects biological communities.
• Develop alternative methods for managing and regulating stormwater discharges which are sensitive to arid Western settings by considering effects on biological communities.
• Quantify the fate and effects of nitrogen transformations that occur at the soil/water interface as surface waters percolate into ground waters. Necessary to know the effect of this issue on subsurface biological communities.

Ecological Criteria and Standards

• Develop a list of indicator terrestrial and aquatic species in ephemeral and effluent-dependent streams in the arid West not currently included in national criteria documents.
• Develop expanded list of species identified in ephemeral and effluent-dependent streams.
• Evaluate food chains representative of important arid West wildlife species, including threatened and endangered (T&E) species.
• Evaluate tissue concentrations in aquatic life and wildlife for mercury, selenium and other bioaccumulative pollutants. Evaluate effect of biochemical pollutants on human health.
• Endangered Species Act (ESA) - what is the impact on water quality standards; bioaccumulation; and manmade systems implementation.
• Protection of habitats/uses through minimum discharge requirements including riparian systems.
• Address the interface between water quality and water quantity.
• Develop an "Effluent-Created Ecosystem" use definition for ephemeral and effluent-dependent ecosystems in terms of the physical, biological and chemical characteristics found in these environments in the arid West.
• Develop protocols for developing criteria appropriate for ephemeral and effluent-dependent waters (EDWs).
• Develop arid West-sensitive protocols for evaluating economic impacts of standards implementation for use in use attainability analyses.
• What are arid species? Are the species in a natural stream the same as the species in a created stream?
• Analyze impact of tribal water quality standards to surrounding state standards. Analyze the impact of differing standards on adjacent states.
• Review toxins standards guidelines - numeric/narrative, including effluent toxicity guidelines.
• Develop data on actual biological systems needed to assess the feasibility of developing wildlife criteria, e.g., mercury.
• Use a more complete array of species to access feasibility for developing wildlife criteria, e.g., amphibians.

Relevant Issues from PCRWRD's Outreach Program Response

• A proposal for a study to address ecological/water quality issues -- differences in function of riparian ecosystems located along effluent and non-effluent-dependent arid Western rivers;
• A proposal to conduct bioassessment survey studies, chemical specific testing of in-channel stormwater run-off, use attainability studies and whole effluent toxicity testing in the arid West for stormwater.

Additional Considerations For Research

• Ephemeral Streams

  - Characterize the biotic community, i.e., types of organisms and life cycle

  - What index period is the most appropriate for sampling in ephemeral streams?

  - Identify candidate metrics

  - Does the hyporheic (saturated sediment beneath or besides rivers and streams) zone function as a refuge for organisms during dry periods? If so, could the most sensitive of these organisms function as indicators of biological integrity for ephemeral streams?

• Methods

  - Develop/evaluate methods for biological assessment in arid streams, including the hyporheic zone - example: are existing methods appropriate for all streams in arid areas?

  - Test and validate classification approaches for biocriteria development in arid systems - example: ecoregions?

• Effluent-dependent waters

  - Identify organisms which could function as indicators of biological integrity in effluent-dependent streams (biological targets--differentiate between reference condition and degraded waters)

  - How do you characterize reference conditions for effluent-dependent waters?

• Other

  - How does de-watering of a stream affect in-stream and hyporheic zone organisms?

  - Implementation of water quality programs

  - Conflict between regulatory structure and management objectives

  - Difficulty in getting known science implemented

• Ephemeral vs. effluent-dependent waters

  - Should these systems be treated independently? Do the same questions apply to both types of streams?

• Flow regime considerations necessary in interpreting effects on discharges? e.g., hydrogeology of stream (flow path)
• Needs of riparian zone

  - What is the recovery or mixing zone as related to flow path?

  - Effects of release patterns on downstream biological communities

  - Establish what species are present and decide what species to protect

  - Consider protecting ecological functions of a stream

• How does stormwater relate to the natural environment? That is - what is its role and natural function of the environment?
• What is the natural variability of arid West aquatic systems?
• Effect of non-point source activities - for example: irrigation flow on arid streams
• Address critical population issues of aquatic species before they become threatened
• Expand our scope to other types of desert streams - for example: desert perennial streams
• Determine better ways of evaluating loading from point and nonpoint sources and determine relative importance of each to aquatic systems
• Determine effects of exotic species on natural biological populations.

Session 2: Prioritization of Candidate Research Issues

During the afternoon session, the biological criteria group continued to refine the issues to more accurately deal with the data needs for establishing water quality criteria for arid West streams. In keeping with the conference approach, the group assigned a high, moderate or low ranking to the issues based on the perception of importance and data needs for development of new criteria. The list of research topics and the group=s consensus of relative importance is as follows:

High Priority Research/Study Topics

Establish a biological criteria for ephemeral and effluent-dependent streams.

1. Develop a complete list of aquatic species (algae, invertebrates, amphibians, and fish) and terrestrial species in or using the riparian habitat associated with ephemeral and effluent-dependent streams. Identify species of concern and their habitat requirements.

2. Develop appropriate methods for evaluating the biointegrity of ephemeral and effluent-dependent streams.

• Define the reference condition for ephemeral and effluent-dependent streams.
• Determine the relative importance of the hyporheic zone as an important habitat for biological organisms in ephemeral streams.
• Develop methods for evaluating the biological habitats of arid streams including the hyporheic zone.
• Identify the period most appropriate for sampling ephemeral streams.
• Describe limiting factors that may affect the development of biological communities (e.g., exotic species, physical integrity, flow levels).
• Determine the natural viability of biological communities of all arid West aquatic systems (EDWs, ephemeral, intermittent, and perennial streams).

Stormwater

1. Establish alternative methods for managing and regulating stormwater discharges under arid West conditions by considering effects of stormwater on biological communities.

2. Define the difference between how biological communities are affected by the impacts of stormwater in the natural environment versus stormwater under the influence of anthropogenic activities.

Establish the relationship between water quality and water quantity.

1. Characterize the hydrologic nature of flow in effluent-dependent waters.

2. Determine minimum discharge flow requirements for protection of habitats (including riparian areas) and designated uses.

3. Determine the effect of the mixing and recovery zones on biological communities in the flow path of the discharge.

4. Determine effects of discharge release patterns on downstream biological communities.

Moderate Priority Research/Study Topics

Evaluate the biological effects of pollutant loading from point and nonpoint sources and determine the relative importance of each to ephemeral and effluent-dependent streams.

Low Priority Research/Study Topics

Determine the fate and effects of chemical species transformations that occur at the soil/water interface on biological communities.

Session 3: Application of Biological Research to Criteria

Session 3 focused more specifically on the application of research and new data to assist in the development of specific standards and criteria for arid West streams. The group provided further observations and recommendations for what was felt was relevant research topics needed in the regulatory process.

High Priority Research/Study Topics

Establish Biological Criteria for ephemeral and effluent-dependent streams.

1. Develop a complete list of aquatic species (algae, invertebrates, amphibians, and fish) and terrestrial species in or using the riparian habitat associated with ephemeral and effluent-dependent streams. Identify species of concern and their habitat requirements.

2. Develop appropriate methods for evaluating the biointegrity of ephemeral and effluent-dependent streams.

Determine the variability of biological communities of ephemeral and effluent-dependent streams.

Define the range of biologically acceptable and attainable reference conditions for ephemeral and effluent-dependent streams that offers a net ecological benefit.

Determine the relative importance of the hyporheic zone as an important habitat for biological organisms in ephemeral streams.

Develop methods for evaluating the biological habitats of arid streams including the hyporheic zone.

Identify the most appropriate sampling programs for ephemeral streams (consider seasonal and flow fluctuations).

3. Describe factors that limit the development/sustainability of biological communities (e.g., exotic species, physical integrity, flow levels, chemical characteristics).

Stormwater

Define the difference between how biological communities are affected by the impacts of stormwater in the natural environment versus stormwater under the influence of anthropogenic activities.

Establish the relationship between water quality and water quantity.

1. Characterize the relationship between water quality and the hydrologic nature of flow in effluent-dependent streams.

2. Determine minimum discharge flow requirements for protection of habitats (including riparian areas) and designated uses.

3. Determine the effect of the mixing and recovery zones on biological communities in the flow path of the discharge. This includes determining the fate and effects of chemical species transformations that occur at the soil/water interface on biological communities.

4. Determine effects of discharge release patterns on downstream biological communities.

Evaluate the biological effects of pollutant loading from point and nonpoint sources and determine the relative importance of each to ephemeral and effluent-dependent streams.

Conclusion:

Of the above priority research topics identified by the group, these were specified as the most important for developing data necessary for establishing arid West ecosystems criteria and standards.

1. Determine the variability of biological communities of ephemeral and effluent-dependent streams.

2. Define the range of biologically acceptable and attainable reference conditions for ephemeral and effluent-dependent streams that offers a net ecological benefit.

3.Define the difference between how biological communities are affected by the impacts of stormwater in the natural environment versus stormwater under the influence of anthropogenic activities.

Biological Group - Additional Notes and Comments

Application, Implementation, and Research

High Priority Issues:

Comments on: Establishing biological criteria for ephemeral and effluent-dependent streams

Limit to Sonoran Desert? The focus is not on a particular region but on the whole arid region. Is this implied? Need coordination among states. We do not want to come up with individual approaches for regional or desert or state by state. Need some classification system for the ephemeral and effluent-dependent waters. Establish protocols - sampling everything the same way. Standardized protocols-reducing adversity of methodology. If we were to try and do more than one stream species it would be a daunting task. Maybe make an inventory on a broader scale. Classify the habitats first and then see if we need to list the individual species. The habitat drives the species, each stream and population is different. Include the habitat first if you are going to do a broader area. Needs to be regional to the arid West and not by individual state. Habitats are not always conclusive to individual states but may involve more than one state, not set by boundaries. To get a cross section of the ephemeral and effluent-dependent waters you need a cross-section of ephemeral streams.

Comments on: Developing appropriate methods for evaluating the bio-integrity of ephemeral and effluent-dependent streams.

Reference condition - what do we expect in terms of quality? Attainable under various conditions? There is a series of attainable endpoints. Reference condition for one area may be different for another area. This is a special consideration for this particular stream.

Define practical attainable reference condition for ephemeral and effluent-dependent streams. Attainable under various biological and chemical conditions. We are dealing with managed systems; this gets away from reference conditions. Maybe rather then defining the reference condition we need to define options. There is a range of reference conditions. This is what is reasonably attainable under these conditions. Science that helps define the range of options. Here is what you can do biologically, here are the options. We still have to define the objective - but the reference condition has to be still there. What makes an ephemeral habitat healthy? We need to concentrate on what is a healthy habitat. These are conditions that define what is a healthy habitat. What is a reference condition? How are we going to determine what is a reference condition? Pristine is not a goal.

Acceptable and attainable--what are we trying to attain (reference condition)? What is the minimal that we want to attain? We are talking a concept that is practical and attainable. Economics has to be a factor. Defining a range and having a management decision being made outside of the research. We are mixing goals and science. Bringing a technology-based concept - defining range of options. Look at appropriate reference conditions for the climatic areas.

Put some qualifications in. What is attainable? Practically attainable you have to decide what it is you have - define what is there and then look at options. Discussion centers on what is a reference condition. Reference condition means determine range of what is acceptable or what is attainable for each body type so there is a net equal.

Identify the most appropriate for sampling ephemeral streams.

Describe limiting factors that may affect the development of biological communities (e.g., exotic species, physical integrity, and flow levels)

What new information might be generated? What are new limiting factors that are not already in the literature? We know the array. What is limiting; what is attainable. Needs to be put in context of chemical input.

There are other concerns here - stormwater. This is an implicit type of analysis. This seems self-evident. What is limiting to the biological communities there is an array of things we know-but it might be nice to say the three things that are limiting generally. We would want to know what is the main limiting factor to know where to concentrate funding research. What are the limiting factors to the communities? Is that transferable to the EDWs/some EDWs are going to have to be site specific.

Discussion Summary of #3: Define factors that affect biological communities of ephemeral and effluent-dependent streams.

- Describe the factors that limit the development of biological communities.(e.g., exotic species, physical integrity, and flow levels)

- Determine the natural variability of biological communities of all types of arid West aquatic systems.

- Ephemeral and effluent-dependent streams - determining natural variability - consider natural variability for all others. We need to know the range - the boundaries on what you expect to find; could be site specific issue; practical issues for considering this. Going to have to consider natural variability if you have reference condition. How do we know that is a natural variability? Remove natural and just determine variability. Determine the variability of biological communities of all arid West aquatic systems. Look at reference conditions - look at variability first. Regarding ephemeral and effluent-dependent streams, if the variable is different from ephemeral-and effluent-dependent streams, interpretation might be different. The effluent-dependent and effluent streams are different. Do we need to prove that point? EPA: I think so. Do we want to compare arid West systems with other systems in order to document? We need a classification system.

- Determine the variability of biological communities. Are we trying to find the difference between western perennials and EPA's perennials? Preface statement: Ephemeral effluent-dependent streams are of the most predominant interest.

Biological Group Participants

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