Stream Conservation: Why?
Healthy Streams for Healthy Communities:
Most people are familiar with the fact that clean, healthy streams provide drinking water and recreation in the form of fishing, boating, and swimming; however, these are just a few of the important benefits provided by healthy stream systems. The benefits of healthy streams are often taken for granted until they are gone. When streams become degraded, the equilibria that have evolved in these systems fall out of balance - the consequences of the resulting imbalances come at significant costs to society. Accordingly, many of the benefits that are provided by healthy streams tend to be recognized as costs of degraded streams. Regardless of whether these issues are discussed in terms of benefits or costs, there are clear and long-term societal consequences resulting from how we manage streams in our communities.
Benefits of Healthy Streams:
Drinking Water - Most of Hamilton County gets its drinking water from the Ohio River, the rest of the county obtains drinking water from the Great Miami Buried Valley Aquifer (GMBVA). The GMBVA is continuously exchanging water with the County's large rivers (Great Miami River, the Whitewater River, and the Little Miami River). From these facts, it is clear that maintaining good water quality in our river systems is of paramount importance; however, one cannot protect water quality in larger river systems without protecting the smaller streams from which they are fed (78% of stream miles in Ohio drain ≤ 20 square miles).
Recreation - Recreation in Ohio streams includes activities associated with fishing, fossil hunting, natural exploration, hiking, boating, and swimming. These activities have clear benefits to the health and wellbeing of Hamilton County residents. Stream recreation in Hamilton County also has clear economic benefits resulting from monetary transactions directly associated with the recreational activities (sporting goods, books, etc.) as well as transactions indirectly associated with the recreational activity (transportation, dining, etc.). Typical obstacles to recreation include high levels of fecal bacteria (health hazard), fishery impairment, and access limitations.
Economic Opportunities of Healthy River Corridors - Locally based economic studies have demonstrated that healthy river corridors in Hamilton County have the potential to become major economic assets. Securing rights-of-way along river corridors including adequate riparian buffers, bike trails and river access points has the potential of generation millions of dollars of annual economic activity and would be expected to result in significant increases in property values near these corridors. Learn more by reviewing river resource economic studies for the Lower Great Miami River and the Mill Creek in Hamilton County.
Stable Channels - Stable channels protect property. The shape or flow path pattern of a stream channel controls the capacity of flowing water to erode its bank. Natural stream systems have evolved stable shapes and patterns in response to the flows and sediment loads that they receive. Channel stability falls out of balance when 1) the erosive capacity of the water being delivered to the stream changes (increased runoff), 2) the flow path pattern of the channel is manually changed (straightened), or 3) the sediment load being delivered to the stream changes (through erosion of the landscape). When stream channels become unstable excessive bank erosion can undermine public and private infrastructure (e.g. roads and homes) at significant costs to society and private land owners. Healthy stream systems are geomorphically stable stream systems.
Conservation of Wildlife - Healthy streams are dependent upon both in-stream habitat and healthy riparian corridors. Aquatic wildlife depend upon riparian corridors for shade/temperature control, in-stream cover/refuge, inputs of energy sources (leaf litter and woody debris), streambank stabilization, and removal of pollution and sediment from incoming stormwater. Riparian corridors also function as habitat for terrestrial wildlife in the form of primary habitat, refuge, and corridors connecting primary habitats. Streams themselves provide terrestrial wildlife with drinking water, food, refuge, and aquatic life stage habitat. Conservation of healthy stream corridors constitutes low hanging fruit for wildlife conservation generally.
Assimilation of Nutrients and Organic Matter - Healthy stream are dependent upon a diverse assemblage of macro- and microscope organisms for efficient processing of nutrients and organic matter. Efficient assimilation of nutrients and organic matter is important to reduce nutrient pollution and efficiently recycle leaf litter and woody debris.
Healthy streams, including both a diverse assemblage of aquatic organism and a wooded riparian zone (100 feet or more from each bank), efficiently incorporate excess nutrients into organic tissues of desirable aquatic organisms and riparian vegetation. In healthy streams, primary producers (phytoplankton, non-nuisance algae, macrophytes, and riparian vegetation) uptake nutrients which are then slowly cycled through multiple food chains and retained in the stream for relatively long periods of time. In degraded streams, due to lack shading and lack of complexity in the structure of aquatic organisms, nutrient pollution can trigger nuisance algal blooms leading to nutrients "spiraling" through the system and being exported downstream relatively quickly.
Leaf litter and woody debris that fall from trees and shrubs eventually are delivered to streams. Leaf litter and woody debris are not digestible to most animals, but within a couple weeks of entering a healthy streams, fungi and bacteria soften and transform this material to "coarse particulate organic matter" (CPOM). At this point groups of aquatic macroinvertebrate (bugs) called "shredders" begin feeding on the material further breaking it down into "fine particulate organic matter" (FPOM; pieces less than 1mm in diameter). FPOM is fed upon by "filter feeding" macroinvertebrates and some fish species. Anyone who has raked leaves in the fall or regularly picked up fallen sticks in a wooded back yard can appreciate how quickly organic matter can accumulate. Healthy stream ecosystems provide the critical service of breaking this material down so it does not accumulate in downstream river systems.
Removal of nutrients is most efficient in smaller headwater streams, (≤ 20 square mile drainage area) which make up more the 78% of stream miles in Ohio. Similarly, much of the early processing of organic matter occurs in headwater streams where leaf litter and woody debris represent the primary energy source as shading from woody riparian vegetation limits photosynthesis in healthy streams. This represents one example of why headwater stream conservation is critical for downstream river conservation (other examples include water quality inputs from headwater streams, sediment pollution originating from headwater streambank erosion, and headwater stream functions as refuge and metapopulation habitats).
Biomonitoring - In the State of Ohio, and many other states and countries around the world, the water quality standards by which streams are evaluated are based on biological criteria (index scores for fish and macroinvertebrate communities). There are many reasons to monitor biological communities in streams as a means to assess water quality. Biomonitoring in streams serves a "canary in the coal mine" function. Aquatic organisms have varying levels of tolerance to different types of pollutants, habitat impacts, and hydrologic alterations. A diverse assemblage of fishes and macroinvertebrates within a healthy stream ecosystem offers a spectrum of responses to various stressors; however, there is little value of having a canary in a coal mine if the carary is dead.
Viewers of crime scene investigation TV shows, may have been led to believe that the technology exists to take a sample and run a single test to find out what pollutants may be present; however, in reality separate analyses must be run for every parameter (pollutant) for which one would like to test a water sample. Samples for each of these parameters many need to be preserved differently, they may have different requirements for how fast they must be delivered to an appropriate laboratory or at what temperature must be maintained; and different laboratories have capabilities to test for some parameters but not others. The interaction of chemicals with each other, and with in-stream physical structure and biology, are complex and difficult to interpret. Biomonitoring can be used as a screening tool to efficiently establish whether or not there is a need for further investigation of chemical water quality.
Another advantage of biomonitoring is increased temporal relevance of the sample. When we test for a chemical parameter, the result represents a snap-shot in space and time - the chemical concentration in the precise location where the sample was taken at the precise moment that it was taken. In contrast, the long life-cycles and sedentary nature of many aquatic organisms allows for detection of intermittent and spatially varying stressors that may not be present at the time and location of sampling.