Section 1: Introduction and Executive Summary

Organization of This Report

The findings of this watershed effort are important to several different audiences, including residents and stakeholders in the Mill Creek, the U.S. Environmental Protection Agency (EPA), the Ohio Environmental Protection Agency (OEPA), other state and federal agencies, and other communities pursuing water resource management efforts in complex urban watersheds.

This report begins by summarizing the major findings and recommendations pertinent to efforts for addressing wet weather and other problems in a watershed context. Section 2 provides a brief overview of the Mill Creek Watershed. Section 3 provides an overview of the need for a new approach to dealing with the problems of a complex urban watershed and the Metropolitan Sewer District (MSD) of Greater Cincinnati’s view of what constitutes a watershed approach. Section 4 provides a more detailed explanation of our watershed efforts, the obstacles we encountered, and proposed solutions and next steps.

Executive Summary

The purpose of this effort was to apply watershed principles and approaches to better mange wet weather and other impacts in a complex and highly developed urban watershed, the Mill Creek. This executive summary provides a brief overview of the major findings and recommendations.

·Complex watershed problems require integrated and coordinated analysis and solutions. The Mill Creek Watershed is impacted in almost every imaginable way. Pollution sources include the following:

·Municipal and industrial discharges

·Wet weather point sources, such as combined sewer overflows (CSOs), sanitary sewer overflows (SSOs), and storm water

·Landfills

·Underground storage tanks (USTs)

·Nonpoint sources (urban runoff and agriculture)

In some cases, pollutant sources have been reasonably well characterized and control programs are in place (such as for CSOs). In other cases, the contribution of certain pollutant sources is neither understood nor controlled. Extensive flood control and channelization efforts have reduced flooding problems but have contributed to a substantial loss of habitat throughout the lower half of the Mill Creek. Development and new growth in the upper half of the watershed require immediate attention to ensure that existing problems are not exacerbated or new problems created. Public perception of the Mill Creek was determined to be low because of its aesthetic state and its lack of access and recreational and opportunities.

While MSD and other entities are spending substantial resources on correcting CSOs and SSOs, the watershed process can ensure that other high-priority problems are dealt with. It is clear that improvement in water quality alone will not be adequate to achieve long-term goals for the Mill Creek.

·The diversity of stakeholders and interests in the Mill Creek has contributed to many problems that exist today and has created substantial institutional barriers that prevent meaningful progress on current watershed efforts. Despite the involvement and good intentions of four federal agencies, six state/interstate agencies, 10 local government agencies, 34 local governments, and numerous other constituency groups, the Mill Creek remains a seriously impaired water resource. Yet no single agency or group has responsibility or authority for managing Mill Creek at a watershed level. The present Mill Creek Watershed Council is a positive step in developing a forum for watershed management. However, far greater commitment is needed from key stakeholders since the council lacks the authority to regulate present activity or to implement change.

·Meaningful watershed progress in the Mill Creek has been hampered by the lack of a "common frame of reference." GIS technology is a key tool for organizing and displaying information about the Mill Creek in a way that all stakeholders can access and understand. Despite over 20 studies and reports on the Mill Creek by as many as 11 different agencies and organizations in the last 40 years, stakeholders in the Mill Creek have failed to reach a common view of the resources and problems in the Mill Creek. MSD—with the help of the Cincinnati Area Geographic Information System (CAGIS) and the Cincinnati Office of Environmental Management—developed a geographic information system (GIS) database to organize and manage historical data, display information in a way that the public and decision-makers can understand, and view the watershed in the context of the big picture. We expect this to be an important tool for the Rivers Unlimited Mill Creek Restoration Project (RUMCRP) in its educational and school programs. And although extensive data and information exist in the Mill Creek GIS database, key pieces of information still need to be obtained, such as the location of recreational and open space areas that may in turn help to identify greenway/green space opportunities.

·Past data collection efforts are patchwork approaches that don’t completely characterize the nature and extent of the problems or resources in the Mill Creek. Future data must be collected as part of an overall watershed monitoring strategy. A great deal of data has been collected on the Mill Creek but, in most cases, data has been localized and has focused on specific issues. Consequently, significant gaps exist in the understanding of stream and biotic behavior and of certain pollutant sources.

There is an immediate need for key stakeholders in the Mill Creek to reach agreement on a coordinated strategy for future data collection. As this report is being written, at least three agencies are planning to pursue major environmental monitoring programs in the Mill Creek. This does not begin to include the compliance-monitoring efforts of nearly 20 National Pollutant Discharge Elimination System (NPDES) permittees.

MSD supports the Urban Wet Weather Advisory Committee’s early efforts to develop guidance on watershed-monitoring strategies. As an interesting point, we were unable to identify a comprehensive watershed-monitoring strategy involving several federal, state, and local agencies, for any other urban watershed.

Key data collection and assessment activities should be addressed in future watershed planning, including the following:

·Characterization of all major pollutant inputs to Mill Creek

·Characterization of stream dry and wet weather quality

·Sediment monitoring and evaluation based on biological effects

·Development of a comprehensive stream water quality model

·Evaluation of stream and riparian habitats on a reach-by-reach basis

·Development of long-term biological monitoring stations

·Inventory of significant terrestrial and aquatic biota and biotic refuges

·Inventory of erosion and sediment sites

·Municipal wastewater agencies such as MSD can play an important leadership role in bringing about needed change. The Urban Wet Weather Advisory Committee has been having extensive discussions about ways that wet weather issues can be dealt within a watershed context. In light of our role in wet weather sources of pollution, MSD is prepared to commit to a leadership role through a series of actions. MSD, with the concurrence of the Mill Creek Watershed Council, Butler County, and other stakeholders will do the following:

·Take the lead in developing a consensus-based watershed monitoring strategy

·Take the lead in maintaining the Mill Creek GIS database

·Coordinate GIS database improvement through supplying key missing data

·Consider assigning a Mill Creek watershed coordinator within MSD to coordinate actions with other stakeholders

·While we have made important progress in defining and implementing a watershed approach that seems appropriate for the Mill Creek, an objective measure of progress indicates that substantially more work is needed before an integrated watershed approach is achieved. Based on reviews of many watershed efforts and existing guidance, we began with an initial watershed process that soon changed to reflect the specific needs and situation in the Mill Creek. Currently, we have identified 10 key elements of our watershed approach. Table 1 lists the elements and depicts our current progress.

·The success of the watershed approach is essential if we are to make meaningful progress in addressing the complex problems in the Mill Creek. This grant has helped invigorate efforts and identify important next steps. Table 2 lists the key recommended steps, target completion dates, and lead stakeholders.

Section 2: A Snapshot of the Mill Creek Watershed

The Mill Creek, located in southwestern Ohio, flows 28.1 miles from its headwaters in Butler County through central Hamilton County and the City of Cincinnati to its confluence with the Ohio River. The Mill Creek Watershed encompasses 166.2 square miles with a population of about 450,000. Key facts and demographics on the Mill Creek are shown in Figure 1, and Figure 2 shows a map of the Mill Creek Watershed.

The Mill Creek is in many ways a typical urban watershed: Its current condition is shaped by the past. Significant development, industrial growth, and physical alteration make the Mill Creek a very different water resource than its natural condition.

The changing natural conditions and a chronology of the changes over the past 200 years are chronicled in Dr. Stanley Hedeen’s book, The Mill Creek: An Unnatural History of an Urban Stream, published by RUMCRP. This book is a valuable resource about the major features and conditions of the Mill Creek, which is important to understanding the need for and challenges of applying watershed principles.

Historical Perspective

For the native inhabitants of the Mill Creek area, Hedeen reports that the creek was called Maketewa, its now-forgotten Indian name. Despite ongoing conflicts between the Indians and early settlers in the Maketewa valley, land surveyors and speculators ventured with the early settlers to the area. Surveys conducted in 1788 showed the Mill Creek and its valley entirely covered by a deciduous forest that also enveloped most of the Mill Creek Basin.

Development/Urbanization

Land use in the Mill Creek has evolved since development began in the late 1700s. Even in the early years of development, the creek was recognized as a valuable resource for water supply, agriculture, timber and flour mills, and industrial development. The overall Cincinnati area became a major industrial and transportation center as the United States expanded westward.

Today, Cincinnati and its suburbs have expanded to cover almost the entire watershed. The only portion that has significant areas of undeveloped and agricultural land is the upper reaches of the watershed in Butler County. Industrial and commercial development has seriously encroached on the corridor immediately adjacent to much of the Mill Creek, and the extensive development and the degree of imperviousness result in significant fluctuations in flow and flooding concerns.

Flood Control/Protection in the Lower Mill Creek

Prompted by an ice flow and flood disaster in 1877, the Corps of Engineers’ earliest interest in the Mill Creek involved ideas of constructing an elaborate harbor and port in the Mill Creek or building various ship channels. Although both ideas were later discarded, the corps’ interest in the creek didn’t end there. Repeated flooding from the backspilling of the Ohio into the Mill Creek and from upstream sources captured the corps’ attention, which led to numerous flood control efforts throughout the watershed.

In 1948, construction was completed on the Barrier Dam, which was designed to prevent backflow of the Ohio River into the Mill Creek. (During flood stage in the Ohio, the entire Mill Creek flow is pumped into the Ohio River.) The corps then turned its attention to the second source of flooding—the Mill Creek itself. As of 1992, more than 40 percent of the proposed channelization in Hamilton County had been completed, and much of the natural ecosystem has been replaced with concrete channels, or riprap.

Water Quality

Decades of industrial, commercial, and residential activity in and around the Mill Creek have left their mark. Industrial and municipal discharges, sewer overflows, abandoned landfills and dumps, storm water, agricultural runoff, and other sources contribute to water quality problems to varying and unknown degrees.

Habitat and Biotic Resources

The combined effects of development, channelization, and pollution have also taken a great toll on the Mill Creek. Some areas simply have very limited habitat for fish or wildlife. In fact, fish and macroinvertebrate studies have demonstrated generally poor conditions in most of the Mill Creek. At the same time, significant biotic refuges exist.

Section 3: Setting the Stage for the Watershed Approach

Past Approaches to Water Resources Management: Addressing Problems and Issues in Isolation

The varying missions and priorities of the stakeholder organizations and agencies are largely responsible for the conditions that exist today in the Mill Creek. With the prospect of continued growth and development throughout the Mill Creek Watershed, particularly in the rapidly developing areas of Hamilton and Butler Counties, conditions are likely to improve only with better coordination of resources and activities based on a common vision and shared values and goals.

One example of the problems resulting from conflicts among different organizations’ mission and goals is demonstrated by the past flood control efforts in the Mill Creek. While these efforts were largely successful in alleviating serious flooding, natural habitat conditions in the Mill Creek channel were substantially altered. And the problem persists today. In the interest of maintaining flood control structures, herbicides are applied to the riparian zone and channel to eliminate vegetation. Similarly, ongoing stream channelization efforts are not sensitive to the habitat needs of the watershed.

Environmental regulatory programs can also result in misplaced priorities or solutions that don’t reflect a complete understanding of the watershed problems. Wet weather sources of pollution may be a prime example. Wet weather sources that MSD is currently responsible for—including CSOs, SSOs, and storm water—have historically been viewed as separate and distinct sources. But, in fact, there are great similarities in the frequency, duration, and impact of these sources. Also, some pollution sources that may be far more significant or may even have similar solutions go relatively unnoticed and unattended.

All in all, past efforts in the Mill Creek have produced mixed results. Wastewater treatment efforts in Butler and Hamilton Counties have produced enhanced water quality. Yet future resource expenditures will need to target the most significant problems. For these and other reasons, a new approach to water resources management is needed.

MSD led this part of the Mill Creek Watershed effort to better define our role and identify ways to evaluate and integrate the control of wet weather pollution sources in the context of other problems in the Mill Creek. A brief overview of MSD is provided in Figure 5.

The Need for a New Approach Emerges

Critical decision-making in the Mill Creek Watershed requires a brand-new, locally driven approach in order to achieve the necessary long-term improvement. The watershed approach is the ideal framework for making the right decisions for the Mill Creek. But before defining the framework for the Mill Creek watershed approach, we investigated similar efforts that are underway for other watershed projects.

Substantial Existing Information on the Watershed Approach

The resurgence of interest in the watershed approach during the last five years—which is also relatedly and more recently referred to as "community-based environmental protection"—has produced substantial information and guidance on the subject. MSD reviewed the existing EPA guidance as well as the published literature and papers. In addition, representatives attended conferences such as Watershed ‘96 and the Water Environment Federation (WEF) Urban Wet Weather conference. For example, MSD evaluated watershed efforts that were initiated by similar municipal entities, had substantial contributions by similar municipal entities, or had similar urban watershed stresses, particularly from wet weather sources. Table 3 summarizes three other similar watershed efforts and compares them to the Mill Creek. The Appendix contains a detailed fact sheet on each of these efforts.

A review of these and other watershed efforts led us to several broad conclusions about the watershed approach:

·There is no single, absolute, right process.

·The process is designed to be—and must remain—flexible.

·The level of effort for various watershed efforts is highly variable, ranging from shoestring budgets to multimillion-dollar projects.

·Each watershed has its own set of problems and needs.

·True success, defined as accomplishing the desired environmental results, is hard to achieve, yet progress is nevertheless evident.

·Watershed efforts tend to focus on correcting problems of the past, but they should also aim for problem prevention for the future.

MSD’s View of the Watershed Approach: A Work in Progress

In its simplest terms, the watershed approach is a consensus-based decision-making framework to address water resource issues and needs within a defined geographic area. By its very nature, it is a flexible and dynamic approach.

Based on the insights gained from existing watershed guidance and efforts underway across the United States and Canada, MSD developed an initial approach. By the end of this first year, our approach had been substantially revised to reflect our progress, findings, and challenges.

Figure 6 summarizes the major steps of the watershed approach as applied to the Mill Creek. This approach forms the basis of our discussion of progress, conclusions, and recommended next steps for the Mill Creek.

Section 4: Progress with the Watershed Approach for the Mill Creek

Using the working watershed process as a framework, this section of the report describes progress, key findings, and recommended next steps.

Define the Geographic Area

In a broad sense, we all started by understanding that the Mill Creek Watershed was our geographic area of concern. However, defining the exact location of the watershed boundary using U.S. Geological Survey (USGS) topographic maps did result in some surprises.

Key Findings

·The substantial development and urbanization of the Mill Creek have altered natural flow patterns in and around the Mill Creek, forcing us to recognize the existence of a "natural" watershed boundary as well as a "sewershed" boundary. The sewershed boundary is needed when considering wastewater flows from outside the natural watershed.

·Part of a third county (Warren County) is within the watershed, although it is a small area of less than 50 acres.

·Some previously drawn watershed boundaries excluded the downtown portion of the city of Cincinnati. This is understandable considering the extensive alteration of the flow patterns of the area and the existence of combined sewers, which can result in three different flow patterns, depending on the extent of the wet weather conditions. In fact, based on the sewershed boundary, some of the downtown is not in the watershed.

Recommended Next Steps

·Recognize the dynamic nature of the Mill Creek Watershed boundary in future planning activities.

Identify Key Stakeholders

All key interests must be identified so they can be involved in consensus-building to achieve a shared vision, common goals, and a plan for achieving the desired water resource and environmental outcomes. And while MSD is just one of the many stakeholders in the Mill Creek, this effort provided continued momentum to identify and involve these stakeholders. Figure 7summarizes the Mill Creek stakeholders. In the Appendix, Table 7 provides a complete inventory of the Mill Creek stakeholders, as well as representative names and contact information.

Key Findings

·The range of interests in the Mill Creek is highly diverse—four federal agencies, six state/interstate agencies, 10 local government agencies, 34 local governments, and numerous other constituency groups. This will be a major factor and will pose significant challenges for routine communication and establishing an effective process for reaching ultimate consensus on a watershed plan for the Mill Creek.

Recommended Next Steps

·Ensure that the inventory of stakeholders is maintained, routinely updated, and used for communicating important events and opportunities for involvement.

Ensure Public Awareness

In conjunction with the grant, MSD conducted several outreach activities to provide those interested in the Mill Creek and the surrounding area with a forum for discussion, an avenue for receiving information, and an opportunity to give input about the solutions of the problems facing the watershed. The outreach program had several components:

·Telephone Survey: The Institute for Policy Research at the University of Cincinnati (UC) conducted a telephone survey of 1,085 people in the spring of 1996 at the direction of the Mill Creek Watershed Council and MSD. The goal of the survey was to get the views of a variety of people in the Mill Creek area. The survey focused on several issues:

·Have residents heard of the Mill Creek?

·In the public’s view, what should the council focus its efforts on?

·What is the best approach for working on these issues?

·Is the public interested in a walkway or bikeway along the Mill Creek?

·How should any improvements and/or developments be financed?

·Mail Survey: In early September 1996, MSD developed a survey that was mailed to local officials, such as Hamilton County commissioners, Cincinnati City Council members, the mayor and city manager of Cincinnati, Mill Creek Watershed Council Members, and other interested parties. The survey contained a brief overview of the Mill Creek Watershed and asked questions about the individuals’ views of the Mill Creek and recommendations for measures that should be taken to address these views. A dedicated telephone number was established to provide a "voice" avenue for individuals to call and express their concerns and ideas. The results of this survey are also being compiled.

·Video Documentation: In early June 1996, portions of the 28.1 miles of the Mill Creek were videotaped, from Butler County to the Ohio River. This taping occurred during and just after an unusually heavy rainfall, to provide visual documentation of the creek’s conditions during wet weather. The tape will be used as an educational aid during future public presentations.

·Photography: Many photographs have been taken during the preparation of this report, and even more have been collected from various community sources. These photos helped in documenting the conditions along the Mill Creek. In the future, MSD and other organizations such as the Mill Creek Watershed Council will use them in making presentations to the many communities within the Mill Creek. Not only are the photographs helpful in providing a clear picture of the watershed, but the process of collecting the photos provided an opportunity to educate people about the grant project and to get input from people throughout the watershed.

Key Findings

·The draft project report for MSD and the Watershed Council provides extensive information and demographics on the 1,085 respondents. The key conclusions of the telephone survey are as follows:

·Most Hamilton County residents (87 percent) have heard of Mill Creek.

·Over half of the county residents have a negative perception of the Mill Creek as "polluted" or "dead," "it smells," and it has "sewage and garbage in it."

·Residents say that cleaning up the Mill Creek should be priority for the Mill Creek Watershed Council. Nearly two-thirds of the residents say that the Mill Creek Watershed Council should focus on "seeking government assistance to help clean up the Mill Creek."

·Most residents say that cleaning up the Mill Creek is important. Two-thirds of county residents say this is "very important," while the other one-third says it is "somewhat important."

·Some Hamilton County residents have an interest in a bikeway and walkway along the Mill Creek, with 18 percent saying they are "very interested" and 26 percent saying they are "somewhat interested." However, a majority of Hamilton County residents, 57 percent, are not interested in using a bikeway or walkway.

·Nearly two-thirds of Hamilton County residents are opposed to the idea of a small increase in property tax assessments to help finance the improvements and development of the Mill Creek.

Recommended Next Steps

·Compile and publish the results of the telephone and mail surveys.

·Establish an ongoing public awareness program based on, in part, the findings of the surveys.

·Maintain student education programs.

·Continuing effort is needed to educate the public and solicit views on perceptions of problems, needs, and solutions.

Agree on the Goals and the Process

The Mill Creek watershed falls within the jurisdiction of three county governments as well as over 30 municipal governments. Moreover, state and federal agencies have responsibility for various aspects of pollutant discharge regulation, water quality, and flood control. Since no single agency or group has responsibility or authority for managing Mill Creek at a watershed level, it is difficult to apply a single vision for Mill Creek or to provide the comprehensive planning and regulation that are necessary to achieve that vision. Therefore, given the diversity of roles and interests of the stakeholders, an agreed-upon process is needed to develop a shared vision and plan for improving the conditions in the Mill Creek.

Key Findings

·Organizations such as the Hamilton County Environmental Action Commission, Mill Creek Watershed Council, Ohio-Kentucky-Indiana (OKI) Regional Council of Governments, Rivers Unlimited Mill Creek Restoration Project (RUMCRP), and others have all made important contributions to past Mill Creek efforts. In fact, each of these groups has played a key role in establishing initial watershed-based efforts in the Mill Creek. Also, the Mill Creek Watershed Interjurisdictional Agreement has provided a common vision among the participating local governments to recognize the importance of the Mill Creek and to cooperate in its improvement.

·The present Watershed Council is a very positive step in developing a forum for watershed management. But it lacks the necessary authority to regulate present activity and to implement change.

·Despite the important efforts and contributions of many stakeholders in the Mill Creek Watershed, agreement on a clear and common vision, goals, and process for decision-making in the Mill Creek has eluded us.

·The different missions and perspectives of the various watershed stakeholders have created significant institutional barriers to progress. Examples of these barriers and resulting problems include the following:

·Lack of coordination on collecting environmental-monitoring data

·Flood and erosion control efforts that do not stabilize or improve habitats

Recommended Next Steps

·To further a watershed plan, take steps to ensure that the various government and agency entities agree on common principles and practices (such as storm water management and floodplain management) for watershed management. Each entity must also share in whatever pollution control, flood relief, and restoration works are ultimately proposed.

·Maintain consistent project leadership. MSD, because of its substantial role in the Mill Creek, should be a greater catalyst for progress. Later portions of this report provide specific next-step recommendations that can be pursued to support the watershed process.

·For the time being, strengthen and focus the role of the Watershed Council to provide overall leadership to the Mill Creek watershed restoration effort. The council should also broaden its base to include as many of the stakeholders as possible.

Develop a Common Frame of Reference

MSD believes that an essential step in the watershed process is for stakeholders to have a common source of information and frame of reference about the conditions in the watershed. This has been and continues to be a significant impediment to progress. Without a common understanding of the problems, we believe it is unlikely for watershed stakeholders to agree on a shared vision, goals, or process for making improvements. MSD, as part of this demonstration grant, took the lead to identify existing studies and reports and to apply GIS tools to organize, analyze, and present key information on the Mill Creek.

Achieving a common frame of reference for the Mill Creek meant that we needed a way to accomplish these goals:

·Organize and manage historical information and data.

·Understand the complexity and interrelatedness of the problems in the Mill Creek.

·View the watershed in the context of the "big picture."

·Display information in a way that stakeholders and the public could readily understand.

·Make the information readily available to all stakeholders.

·Use the information as an educational tool.

A GIS is defined as a system of computer hardware, software, procedures, standards, data, and applications for the automation, display, analysis, and maintenance of spatial information. By "spatial information" we mean information about the location and characteristics of real-world geographic entities such as cities, roads, forests, and soils.

When dealing with a geographic area as large and complex as the Mill Creek watershed, the issues of data collection, integration, and analysis take on major importance. Because these issues—and the data describing them—are part of almost every decision to be made, achieving a common frame of reference takes on critical importance.

Key Findings

·There was no comprehensive inventory of past information on the Mill Creek, nor is this information readily accessible or kept in any central location. The OKI Regional Council of Governments did have the most complete collection of existing studies and reports. Appendix Table 8 identifies over 20 studies and reports on the Mill Creek, dating back to 1959.

·A GIS is a valuable tool for organizing key information about conditions in the watershed. A GIS also provides a common frame of reference for assessing problems and establishing priorities As a tool, a GIS is particularly useful in answering questions relating to location, condition, trends, patterns, and data modeling.

·CAGIS, the Cincinnati Area Geographic Information System, is a consortium of public and private entities in the Cincinnati metropolitan area that organized to establish database standards and fund the creation of a common base map of GIS layers of information. Much of the GIS information presented here was obtained from Cincinnati MSD, a member of the CAGIS consortium. Table 4 summarizes data contributors and the information that is available for GIS analysis of the Mill Creek watershed.

·Geographic data on the Mill Creek is of varying quality and extent.

Recommended Next Steps

·Continue to refine the GIS database and fill in key data gaps, including the following:

·Detailed elevational information for both Butler and Warren Counties

·Sewer service information for Butler and Warren Counties showing both service pipes and locations of key information such as pollution sources (for example, CSO/SSO locations)

·Establish a location for and identify an agency responsible for maintaining all GIS information relating to the Mill Creek

·Continue to explore new uses for GIS in analyzing and assessing problems in the Mill Creek including the following:

·Integrating GIS with modeling efforts including nonpoint and water quality

·Using GIS as a tool to better disseminate information about the Mill Creek for public use and access

·Creating a framework for evaluating management alternatives

·Measuring programmatic and environmental progress

Develop a Watershed Monitoring Strategy

As indicated previously, as many as 11 different organizations and agencies have studied, reported on, and collected environmental monitoring data on various aspects of the Mill Creek over the last 40 years. In addition, numerous NPDES point sources are required to conduct effluent monitoring throughout the watershed. Yet it is readily apparent that this historical data was collected for largely single, narrow purposes and not as part of an overall, coordinated monitoring plan for the watershed. As would be expected, the existing data is also of varying quality, and it was collected at different times for different purposes.

Key Findings

·A great deal of data has been collected to describe the state of Mill Creek including resident biological communities. Unfortunately, with the exception of the recent OEPA survey, collection efforts have been localized and have focused on specific issues. Consequently, gaps exist in the understanding of stream and biota behavior and in the sources of pollution discharging to Mill Creek.

·Limited resources demand that future monitoring efforts be coordinated to serve multiple purposes and needs.

·At least three organizations—MSD, the City of Cincinnati, and the OEPA—have plans for substantial monitoring efforts in the Mill Creek Watershed.

Recommended Next Steps

·Address the following key data collection and assessment activities in future watershed planning:

·Characterization of all major pollutant inputs to the Mill Creek

·Characterization of stream dry and wet weather quality

·Sediment monitoring and evaluation based on biological effects

·Development of a comprehensive stream water quality model

·Evaluation of stream and riparian habitat on a reach-by-reach basis

·Development of long-term biological monitoring stations

·Inventory of significant terrestrial and aquatic biota and biotic refuges

·Inventory of erosion/sedimentation sites

·Develop a coordinated monitoring strategy with appropriate and interested stakeholders. Such a strategy should ensure that future data collection efforts are coordinated to maximize value to all stakeholders:

·Future data is comparable and reliable.

·Key gaps in existing data are addressed.

·Future data is readily available to all stakeholders.

·Sufficient quality control/quality assurance issues are addressed.

·Appropriate measures are established to evaluate watershed progress and improvement.

Agree on Problems and Priorities

Integration of data on the Mill Creek using GIS tools has provided an enhanced understanding of the nature and extent of the problems in the Mill Creek. More importantly, these tools have allowed us to understand the interconnectedness of the problems and recognize that solutions must be truly integrated. For example, spending large sums of money on improving water quality will, alone, achieve only limited progress to restore the Mill Creek. Instead, improvements in water quality must be accompanied by protection and improvement of habitats and the riparian zone and greater attention on the effects of the highly variable flow conditions. This section provides a summary assessment of the key issues and problems in the Mill Creek.

Pollutant Sources

Since no comprehensive inventory had been compiled for the Mill Creek, MSD gathered and summarized available information on existing and potential sources of pollution.

Key Findings

·The Mill Creek is subject to a wide variety of pollutant sources throughout its length. Table 5 enumerates the types, numbers, and characteristics of the pollutant sources into Mill Creek. Sources are continuous and intermittent, wet and dry weather, permitted and nonpermitted.

·As is evident from Table 5, wet weather sources play an important role in Mill Creek. Any watershed restoration/protection strategy will need to address appropriate control of these sources. Fortunately, MSD initiatives such as high-water overflow, SSO reduction, and the long-term CSO control plan are already underway with the expectation that improvements in Mill Creek water quality will result. Nevertheless, the significance and characteristics of a number of sources are unknown at present.

·The pollutant contribution from a number of wet and dry weather sources has not yet been characterized. Sources include landfill leachate, underground storage tank (UST) seepage, nonpoint source (nonurban) pollution, small-scale wastewater treatment effluents, and storm water outfall seepage.

·Wet weather sources such as CSOs are significant inputs to lower Mill Creek, particularly the lower 8 river miles (RM).

·The upper portion of Mill Creek—above RM 12.0—receives wet weather inputs that include urban storm water, nonpoint source storm water, and SSOs.

·The increasing urbanization in Butler County will result in increased storm water hydraulic loads unless appropriate measures are taken.

·The degree that landfills and USTs contribute discharges to Mill Creek is presently unclear. The City of Cincinnati is presently evaluating whether a number of landfill sites contribute contaminants to Mill Creek.

Recommended Next Steps

·Develop monitoring/modeling programs to fully characterize inputs to the Mill Creek and to assess their relative significance. Future monitoring will be required to define the magnitude and importance of these sources in determining stream water quality.

·Implement appropriate erosion/sediment and storm water quality controls in connection with any new development in Hamilton and Butler Counties.

Water Quality and Loadings

Stream water quality can have a dramatic impact on stream biota, and it can also impact the aesthetic properties of the stream. Streams with high levels of organic loading experience shifts in both macroinvertebrate and fish species to more pollution-tolerant forms. Toxicants also produce changes in species composition and, if present in sufficient concentration, can seriously depress numbers of aquatic organisms.

As part of this grant, MSD collected stream water quality data from the last five years and consolidated it into a comprehensive database. Six data sources were obtained. The data sources, the location and duration of sampling, and the analytical parameters, as well as the overall database, are included in the GIS.

Key Findings

·The water and sediment quality of Mill Creek are largely determined by the nature of the pollutant inputs to the creek. In some instances, the pollutant inputs have been reasonably well characterized, and programs are in place to control them. Examples of sources with well-defined control programs include WWTP effluents, CSOs, and industrial discharge. In other cases, the contribution of certain pollutant sources to water quality problems is neither understood nor well controlled. Examples of presently uncontrolled sources include leachates from select landfills and underground storage facilities (if any), nonpoint source runoff and dry weather discharges (such as outfall seepage) that contribute to elevated dry weather stream bacteria.

·Low dissolved oxygen, particularly when coupled with excess ammonia levels, can result in increased stress to aquatic organisms and limit the success of biological communities. Phosphorus results in excess algae growth and increased diurnal oxygen cycling. Both these effects have been observed in Mill Creek.

·The preponderance of stream water quality data is taken in dry weather. In fact, very little wet weather characterization of Mill Creek has taken place with the exception of ongoing ORSANCO monitoring near the mouth of Mill Creek. This data should be included in the database when available.

·Most previous data-gathering has focused on fecal coliform data at selected locations. The only comprehensive recent data collection program was the 1992 Ohio EPA evaluation of Mill Creek. No long-term water quality stations were available to assess stream trends.

·The most recent, comprehensive assessment of Mill Creek water quality was carried out by the Ohio EPA in the 1992 survey. The water quality assessment included a broad range of conventional parameters, heavy metals, and selected organics. The survey showed that instream fecal bacteria exceeded Ohio Water Quality Standards (WQS) throughout virtually all of Mill Creek. The data presented in Figure 9 reflects dry weather conditions. This clearly shows that most of Mill Creek was out of compliance with respect to recreational criteria virtually all the time (whether dry or wet). Other water quality parameters were also exceeded during this survey, including phosphorus, ammonia, and selected chlororganic pesticides. Low dissolved oxygen levels (below Ohio WQS) were also observed in the mainstream of Mill Creek in the lower 2.9 miles and in a number of Mill Creek tributaries.

Recommended Next Steps

·Address both wet and dry weather sources of contamination as part of an overall watershed strategy. The interaction of the various sources in determining stream water quality and hence the benefits of controlling a particular source should be assessed through a program of stream monitoring as well as through development of a water quality model.

·Maintain and update the water quality database developed in this study as new information is collected in the watershed.

·Carry out a comprehensive assessment of wet and dry stream water quality to properly define the current conditions in Mill Creek.

·Consider establishing long-term water quality and quantity monitoring stations on the Mill Creek.

·Initiate a rigorous investigation and correction program of dry weather pollutant inputs to Mill Creek.

Sediment Quality

Sediment quality reflects the history of pollutant inputs into a stream and can therefore be used as an indicator of past and present undesirable discharges. The quality of in-place sediments also directly affects the viability of stream biota, particularly macroinvertebrate communities.

We summarized sediment data from the last five years into a database by stream location. Two major sediment surveys were used in formulating the database:

·In 1992, the Ohio EPA evaluated sediment quality at 18 sites throughout the Mill Creek basin. Sediment analyses included a range of heavy metals as well as organic compounds.

·In May 1993, the City of Cincinnati—in conjunction with CSX Transportation—initiated a baseline environmental assessment of the so-called Section 8 (from RM 0 to RM 1.5) of Mill Creek. Part of this investigation included an evaluation of sediment quality in Section 8. Sediment analyses again included a range of heavy metals and organic compounds.

Key Findings

·The urban/industrial inputs into Mill Creek are reflected by the elevated concentrations of the following parameters: lead, chromium, copper, zinc, mercury, total PCBs, and pesticides.

·Using the bioeffects-based criteria for sediment evaluation, sediment locations and parameters that correspond to severe effects levels are located as follows:

·RM 1.0: Lead, copper

·RM 1.5: Mercury

·RM 1.67: Mercury

·RM 2.9: Copper

·RM 5.2: Copper

·Effects-based assessments have not been developed for PCBs or organochlorine pesticides, but PCB levels are highly elevated from RM 13.13 to RM 16.5.

Recommended Next Steps

·Carry out a comprehensive sediment survey in the future in connection with biological monitoring.

·Use effects-based assessments of sediment quality to examine potential impacts on biota.

·Locate additional sediment monitoring sites in relation to new pollutant inputs identified in this study or in the future.

Habitat

The Mill Creek has been modified in many ways. This has had a dramatic impact on habitat conditions throughout the Mill Creek. The basin was originally forest or grassland, while today much of it is densely urbanized. In studies of various watersheds, Schueler has shown that, as the degree of imperviousness in a watershed increases, the likelihood of success of instream biological communities decreases. Figure 11 shows the relationship of biological community quality to catchment imperviousness. At rates above 10 percent imperviousness, stream biology declines. For the Mill Creek, the lower portion of the watershed is estimated to be in excess of 30 percent imperviousness. But in the upper watershed, the present agricultural areas are very low imperviousness (less than 10 percent). However, new development in the upper watershed may change this relationship.

Urban pervious areas may also significantly influence tributary streams. Schueler estimates that about one-third of all pervious cover in an urban landscape can be considered "high-input turf." High-input turf is a lawn area with heavy rates of irrigation, fertilization, and pesticide/herbicide use. These areas can and do lead to the export of nutrients and organic compounds with resultant stream impacts in terms of eutrophication and toxins entering the water and sediment. The lower portions of the Mill Creek watershed would contain a substantial area of high-input turf.

The stream habitat was evaluated in 1992 using standard Ohio EPA methods (OEPA, 1989). This method produces a numerical index value of a metric called the Qualitative Habitat Evaluation Index (QHEI). QHEI scores of 60 or above suggest habitat of sufficient quality tosustain a diverse warm-water fishery. As the index declines, the likelihood of a diverse and robust fishery also declines. Figure 11 presents the results of the habitat scoring for selected stream stations on Mill Creek. The results have been interpolated to give reach values of QHEI scores. The lower 3.1 miles clearly show the effects of channelization and the loss of adjacent riparian areas, as reflected by very low scores. Above RM 5.1, the stream habitat quality is generally good with reaches of excellent habitat.

Key Findings

·The habitat of Mill Creek has been profoundly modified. The channel form has been realigned and channelized in a number of reaches with consequent loss of stream habitat.

·Much of the riparian cover adjacent to the mainstem of Mill Creek has been removed. Upper tributaries still have significant riparian canopies and, in many cases, good-quality stream habitats.

·Both the pervious and impervious urban areas impact water and sediment quality and biological success in Mill Creek.

·Habitat scores show that the channelized portions below RM 3.1 have very poor habitat with little chance of supporting diverse warm-water fish populations.

·QHEI scores above RM 5.1 indicate the possibility of an improved biological community, based on perceived habitat conditions. Nevertheless, other factors may be the determinants of stream community success.

Recommended Next Steps

·Carry out comprehensive reach-by-reach evaluation of stream habitat for the Mill Creek and its major tributaries.

·Establish a plan by stakeholders for stream habitat restoration in the lower reaches of Mill Creek and habitat conservation/protection in the upper portions of the watershed.

·Where possible, restore riparian cover.

·Make an effort to preserve areas of high-quality stream.

Stream Biological Communities

The comparison and richness of macroinvertebrate communities are direct indicators of water and sediment quality as well as other factors such as habitat and flow regime. We used two sources of data to assess the quality of macroinvertebrate communities in Mill Creek:

·A macroinvertebrate dataset was obtained from Dr. Hedeen of Xavier University. It shows changes in Mill Creek species diversity from 1971 to 1992.

·We used fish population data measured by the Ohio EPA during a 1992 survey to assess the quality of fish populations in Mill Creek. OEPA standard practice is to calculate an index value called the Index of Biotic Integrity (IBI) to capture the richness and diversity of fish species.

Key Findings

·Macroinvertebrate communities are very poor in the lower 3.1 miles of Mill Creek. A number of factors including poor sediment quality and limited habitat probably influence macroinvertebrate performance.

·Macroinvertebrate communities are fair to poor throughout most of Mill Creek. The best communities (those that are marginally good) were observed in the headwater areas of the creek, which correspond to the least urbanized areas of Mill Creek.

·Pressure on the headwater communities will increase with increasing development.

·Historical macroinvertebrate data shows recovery of Mill Creek above RM 7.8 during the last 20 years. Below RM 5.8, very little change has been observed.

·Fish population data shows that only the East Fork of Mill Creek (the headwaters) meets Ohio biological WQS. These headwater fish populations may face pressure as urbanization increases in the upper reaches of Mill Creek.

·The remainder of Mill Creek does not meet Ohio WQS for fish populations. The poor fish populations are probably the result of the interaction of many factors, including poor stream habitat, periodic adverse water quality, and loss of riparian zones.

Recommended Next Steps

·Establish permanent fish and macroinvertebrate monitoring stations throughout Mill Creek to record progress toward meeting stream biological goals.

·Develop a plan for improving stream habitat and riparian cover in selected reaches of Mill Creek (see the discussion of habitat).

Biotic Reserves

Dr. Hedeen prepared an inventory of biotic refuges in the Mill Creek basin. Table 6 enumerates the refuges, their locations, and their special features; Figure 12 shows the refuge locations. These locations represent important repositories of aquatic and terrestrial biota in Mill Creekbasin. Considering the intense urbanization the basin has undergone, it is encouraging that these resources still exist.

Key Findings

·A total of 22 aquatic and terrestrial biotic refuges have been identified within the Mill Creek watershed. At present, little detail is available about the terrestrial communities, and even less detail is available about aquatic communities.

Recommended Next Steps

·As part of developing an overall watershed strategy, prepare an inventory of significant terrestrial and aquatic biota in the Mill Creek watershed. Devote a parallel effort to delineating and mapping the significant biotic reserves.

·Formulate and implement basin-wide biotic refuge protection strategies.

Hydrology and Floodplain Management

The available historical flow records for Mill Creek were analyzed to define the general flow characteristics of the water course. Mill Creek flows at Carthage, Ohio, were analyzed for a 46-year record. In addition to an assessment of average flow, both flood and drought conditions were addressed using conventional flow frequency analysis techniques. This flow analysis provides some of the necessary technical background in support of a comprehensive watershed assessment.

Mill Creek has been subject to historic flooding that has necessitated creating channelized segments to provide adequate conveyance capacity. The floodline mapping of Mill Creek is presently being updated and is expected to be available in spring of 1997. Part of the issue associated with flood protection is the regulation of the floodplain. Due to present encroachments in the developed reaches of Mill Creek, it may be very difficult to return the floodplain to pre-urban use. However, opportunities still exist in the undeveloped portions of the watershed to control development in floodplain areas while also ensuring riparian zones and greenways for future communities.

Key Findings

·Mill Creek experiences an extreme range of flows through four orders of magnitude. The lowest 7Q₁₀ flows occur in November with a flow of 4.32 CFS. Summertime 7Q₁₀ flows are in the range of 7 to 10 CFS. Average flows in Mill Creek are 35 CFS, while 90percent of flows exceed 10 CFS. Peak instantaneous flood flows for a two-year flood are approximately 4,380 CFS, while 100-year flood flows are in excess of 10,000 CFS.

·The wide range of flows as well as the "flashy" nature of urban hydrographs adversely impact biota and result in channel erosion and sedimentation.

·Significant development exists within the present floodplain. Indeed, in some instances, development has encroached directly on stream banks. This development is at risk from flooding and is moreover undesirable from the viewpoint of maintaining riparian zones and the all-important links between stream and land.

·There appears to be no watershed- or subwatershed-level planning to link the impacts of new growth with existing stream flooding and erosion. Rather, a policy of pre- or post-development runoff volume control has been adopted. The operation of storm water detention facilities sized in this manner doesn’t take into account the combined effects of multiple extended hydrographs on stream bank erosion or on biota.

Recommended Next Steps

·Develop options for at least maintaining if not increasing base flow in the Mill Creek.

·At completion of the 1997 floodline mapping, ensure that the hazard lands are clearly identified. Take appropriate measures to mitigate flooding hazards. Flood mitigation should directly tie in with any future program undertaken by the Corps of Engineers.

·Where possible, avoid future encroachments on the floodplain, and adopt a comprehensive floodplain management policy by the municipal stakeholders in the watershed. One possible means of limiting future encroachment would be to implement a public greenway system along Mill Creek.

Erosion and Sedimentation

Urbanization and the resulting increase in peak flow magnitude and duration have led to channel instability in Mill Creek. Segments of Mill Creek are consequently subject to either erosion or sedimentation. Figure 13 shows the substantial sedimentation occurring in the lower channelized reach of Mill Creek (at about RM 3.0).

In contrast, Figure 14 shows bank erosion and undercutting at a location upstream of Figure 13. Both conditions are typical of Mill Creek.

Key Findings

·Bank erosion and undercutting as well as substantial sedimentation indicate channel instability in Mill Creek.

·Owners of property that is adjacent to the stream bank are in peril of losing property and facilities in eroding areas. A number of property owners have taken the initiative of using construction debris to facilitate bank stabilization. The use of debris is unsightly and often only exacerbates erosion at another location.

·The sedimentation observed particularly in the lower Mill Creek leads to loss of channel conveyance capacity, and it adversely impacts the stream bottom habitat.

Recommended Next Steps

·Identify and document areas of erosion and sedimentation in Mill Creek.

·Apply appropriate bank stabilization measures to erosion sites. Bioengineering techniques offer an aesthetic approach to erosion control.

·Regulate and, if possible, prohibit disposal of construction debris in Mill Creek.

Recreation and Public Access Opportunities

The general public perception of Mill Creek is in part tied to its aesthetic state. Impoundments such as Sharon Woods Lake and Winton Lake already have recreational amenities tied to adjacent park areas. The parks at both impoundments have extensive hiking and bike trails as well as well-established riparian areas. Other minor tributaries in the upper watershed area are also well treed and in many cases have informal trails that are well used by local residents. It is in the lower watershed that the greatest challenges lie to improve stream aesthetics and create green space adjacent to the stream. In some reaches (such as Ivorydale) greenways or even stream access may not be practical. In other areas, opportunities exist to create better stream habitats and to create adjacent riparian zones/greenways.

Key Findings

·No comprehensive inventory of recreation, open space, and public access opportunities in the watershed exists. This type of inventory could help identify greenspace and greenway opportunities, protect sensitive areas, and provide for increased protection for sensitive habitat areas.

Recommended Next Steps

·Prepare an inventory of recreation, open space, and public lands.

·Fully explore opportunities for development of an overall greenway plan as part of the mission of the watershed strategy.

Evaluate Alternatives

In an ideal situation, stakeholders would agree on problems and priorities before any evaluation of alternatives. The challenge in the Mill Creek will be to integrate ongoing efforts (such as implementation of CSO and SSO controls) with an improved understanding of the priority watershed problems and to reconcile differences with the support of all stakeholders. At this stage, it is unlikely that Mill Creek stakeholders will agree on significant, new initiatives until broad agreement is reached on the value of the future efforts for the Mill Creek.

Implementation of the recommended next steps should set the stage for a comprehensive evaluation of management alternatives, expected costs, and anticipated benefits.