Tennessee River Resource Stewardship and Protection: The Tennessee River Line Trail Project and Partnerships

The Tennessee River had a long and colorful history of transporting Native Americans, settlers, armies, and cargo of all types in 1700s and 1800s. The headwaters of the Tennessee River, the largest tributary of the Ohio River, originates in the Appalachian Mountains of eastern United States. Created by the confluence of the Holston and French Broad rivers at Knoxville, the Tennessee River flows approximately 1049 km to Paducah, Kentucky where it drains into the Ohio River. This paper highlights how the landscape and geological resources of the Tennessee River and tributaries watershed contributed to the successful economic development of this historical region of North America. The Tennessee River is one of the most biologically diverse freshwater systems in the United States. Environmental challenges included an unsuccessful attempt to keep invasive species, such as the Asian carp, out of the Tennessee River and the Kentucky Lake. The 1049 river kilometer Tennessee River regional trail system with charter River Towns was designed to promote recreational tourism, increase the use of the Tennessee River and to create generations of people who care about the river and are willing to provide environmental stewardship of the watershed resources and protect the river.


Introduction
The Cherokee Indians called the river "hogoheeggee" meaning "Big River" while   [3] upland waters from seven states drain into the Ohio River at Paducah. Published with copyright permission from Book Editor of Soil and Water Conservation Society [3]. Map created by Mic Greenberg. Journal of Water Resource and Protection 248 m and the discharge elevation is 92 m at the confluence of the Tennessee River and the Ohio River. The average Tennessee River discharge is 2000 m 3 /s and the watershed is 105,870 km 2 . Approximately 17,000 recreational boats travel each year along the river, which is used for pleasure and leisure as well as for-profit [2].
The Tennessee River was the western boundary for lands open to settlement until 1818 when the Jackson Purchase pushed the boundary and many Native Americans beyond the Mississippi River [1].   The starting point of the Tennessee River as well as state land and water rights have been the subject of much debate. In 1890 a federal law declared the Tennessee River to begin where the Holston River and the French Broad River come together southeast of Knoxville, Tennessee ( Figure 1). In 1796, when Tennessee was admitted to the Union, the border between Georgia and Tennessee was originally defined as the 35 th parallel, thereby ensuring that at least part of the river would be located in Georgia ( Figure 2). As a result of an erroneous survey conducted in 1818, the actual border was set 1.6 km south of 35˚ latitude which placed the entire river in Tennessee. Georgia has made many attempts since the 1890s to correct the erroneous survey line which resulted in significant Georgia land and population being in Tennessee. Eventually, if state negotiations continue to fail, the border issue could end up in the U.S. Supreme Court.
The primary objectives of the paper are: 1) To document how the landscape and geological resources of the Tennessee River have contributed to the successful water resource and economic development of a historically region in North America; 2) To identify the natural and environmental resource risks to the Tennessee River basin; 3) Document the Tennessee River regional trail system with the goal of creating more community access points along the 1049 river kilometer Tennessee River pathway; 4) To create generations of people who care about the environmental stewardship and protection of the river and landscape resources.

Paducah, Kentucky Is at the Confluence of the Tennessee and Ohio Rivers
Paducah, Kentucky was built on the southern banks of the Ohio River at the confluence with the Tennessee River ( Figure 5). This port city (

Tennessee Valley 1930s and 1940s
The

Tennessee Valley Authority (TVA)
In 1930s the country was in the Great Depression, President Roosevelt created the "New Deal" to help America recover. TVA was founded to help the hard hit Tennessee River Valley recover and improve the quality of life the people living in the valley. The TVA's mandate included controlling flooding on the wild Tennessee River. TVA's first task was to even out the flooding and drought extremes by building a system of dams and lakes to generate power, control flooding and create a system of water management for the greatest possible public good. Figure 11. Red eroded soil since the soils contain hematite. Agricultural practices including row crops in the 1930s resulted in the loss topsoil and reduced productivity.
Faced with a large portion of the U.S. population unemployed and unable to support themselves, President Franklin Roosevelt and Congress created a number of social, environmental, and economic government programs. Legislation in 1933 authorized the TVA, a public-private institution designed to produce low-cost electricity using hydropower and revitalize poor rural regions throughout the south. The largest public power provider in the United States, TVA served an area covering 207,200 km 2 ranging from Tennessee, parts of Alabama, Kentucky, Georgia, and Mississippi to Virginia and North Carolina ( Figure 2). During World War II, TVA hydropower produced electricity for critical war industries including aluminum plants that built bombs and airplanes. At its peak production in 1942, 12 steam plants and hydroelectric projects were under construction at the same time; and design and construction efforts employed 28,000 labors [7]. Today, TVA directly produces electricity for 56 industries and federal facilities and 155 local distributors who provide power to over 9 million people.
The first chairman of the TVA, Arthur Morgan, was an engineer with a vision for large scale, comprehensive planning that integrated building dam projects, public works employment and the transformation of poor rural communities in the Tennessee valley [8]. Morgan's social engineering and dam projects on the Miami River (Ohio) after the flood of 1918 offered a prototype for his problem-solving approach to address resource management and community development. The TVA attempted to balance social, economic, land use and natural resource management of the region in the development of electric power production, flood control, navigation, malaria prevention, erosion control reforestation, and employment. The TVA continues to operate on the principle of integrated solutions even as issues have changed over time.
TVA's River Forecast Center, located in Knoxville, Tennessee, is staffed 24 hours a day to monitor the river to control flooding and to provide water quality, availability and water demand data. In 1933, the TVA headquarters was required by a Congressional mandate to be created on the banks of the Tennessee River and not on a tributary, such as the Holston River [7]. For this reason, the headquarters was moved from Lenoir City to Knoxville and the confluence of French Broad and Holston Rivers.
Dam construction to harness the region's rivers was the cornerstone of the TVA ( Figure 12). The dams controlled floods, generated electricity, improved navigation and provided jobs. Concurrent to building dams and rural electrification, TVA undertook rural development by teaching farmers erosion control practices to prevent soil loss and introducing fertilizers that improved crop yields. TVA also invested in the replanting of forests, better forest fire management, and preservation of wildlife habitat. Electricity generated by TVA dams (Figure 13) modernized rural farms and homes by providing electricity for lights, motors, and other power equipment.

Construction of the Kentucky Dam on the Tennessee River
One of the most powerful weapons for averting flood disasters and reducing the Journal of Water Resource and Protection  The dam is one of the largest human constructed reservoirs built to store excess floodwater and produce electricity ( Figure 15). In the late 1800s the most pressing inland river policy issues focused on encouraging industrialization, westward expansion and assuring navigation on the Ohio and Mississippi rivers [6]. Although high water was an expected seasonal occurrence, large flood events ( Figure 16) only became a major concern as they collided with increasing settlement and industry development along river valleys. The disastrous flood of Figure 14. The Kentucky Dam and Lake on the Tennessee River, upstream from Paducah, control the release of water from the Tennessee River into the Ohio River. This reservoir can store excess floodwater or ensure sufficient downstream navigation depths during drought periods. Published with copyright permission from Book Editor of Soil and Water Conservation Society [3]. Map created by Mic Greenberg.  to reimagine river basins as unique ecological units and to more purposefully manage them as watersheds. A 1908 report by the Inland Waterways Commission called for multipurpose dams, but it took another 30 years and a sequence major river flood disasters (1913,1927,(1936)(1937) before the Federal government, with public support, took leadership in constructing the system of dams and reservoirs we have today in the Ohio River basin [4] [5] [6].
During the 1937 flood, many communities along the Ohio River experienced water 4.5 m above previous records in their downtowns; loss of lives and property; disruptions to railroad traffic and the regional economy in the eastern half of the United States; and loss of telegraph connections and communication functions throughout much of the Ohio Valley. Paducah, Kentucky, at the confluence of the Tennessee and Ohio rivers, evacuated more than 27,000 of their 33,000 population [4] and lost most of their downtown. Paducah today is a thriving city which owes much of it character and revival to the painful destruction of its city in the 1937 flood. Its back-to-the-river renaissance now celebrates its river history with new industries, downtown redevelopment, riverfront stores and museums, and a floodwall which documents historical river events [6]. This spirit of recovery for Paducah is made possible by the 4 m floodwall ( Figure 6) and 1940's construction of the Kentucky Dam ( Figure 15) [7], a 294 km long reservoir which holds back and stores 494,378 hectare-m from the Tennessee River before releasing it into the Ohio River.
Upstream dam and reservoir construction is the most straight forward strategy for downstream flood protection. Dams hold back high volume runoff water from upland spring snow melt and extreme and prolonged periods of precipitation. This allows for the slow release of water downstream thereby managing river height and velocities and limiting potential flood damage. Five dams built in the early 1900's in the Miami Valley (Ohio) by a consortium of public and private interests withstood the 1937 flood in the Ohio River valley and demonstrated the effectiveness of river surveys, topographical maps, a network of gaging stations, and well sited reservoirs [4]. Lessons learned from the construction and management of these early dams provided the TVA with engineering and survey mapping knowledge and reaffirmed the value of comprehensive planning. As

Ecological Impacts of Changes to the Tennessee River LandScape
TVA dam construction on the Tennessee river and tributaries has re-aligned the river flow patterns, temperatures and sediment transport thereby modifying aquatic and terrestrial habitats [9] [11] [12]. Hydropower demands resulted in timed water releases to meet power production needs without regard to aquatic ecosystem impacts. Consequently, water depth and velocities in tail waters below the dam before it flows into the next reservoir during non-generation periods declined to very low levels. Further, reservoir conditions and the dam structure produced low dissolved oxygen (DO) concentrations the low tail waters exacerbating the aquatic ecosystem conditions [11]. In 1991, TVA put in place a Reservoir Releases Improvement Plan to address deteriorating ecological conditions in the Tennessee watershed. Modifications included the installation of fish Journal of Water Resource and Protection ladders and experiments in adding DO and changing the minimum flow to tail waters by modifying timing, velocity, and quantity of periodic water releases. A variety of strategies are used to increase DO including pumps, turbine venting, air blowers, forced air turbine venting, infuser weirs, and line diffusers [11].
A number of studies have begun to monitor dam modifications and impacts on abiotic and biotic conditions and the abundance and diversity of fish species to better understand the extent to which these modifications mitigate and restore the ecology of the river. Of particular interest are changes in discharge fluctuations into tail waters associated with peaking hydropower operations. Monitoring data below nine dams showed yearly and mean minimum velocity and mean DO increased following dam modifications. Flow changes alone had a smaller benefit than the combined effects of increased flow and increased DO [11].
The Cumberland and Tennessee river basins-considered a single aquatic ecoregion-contains one of the most diverse temperate freshwater species in the North America, including 231 fish species, mussels, crayfish, and salamanders [9]. However, urbanization, mining, logging, agriculture, river channelization and dams have accelerated erosion and sedimentation, changed stream flows, and degraded or destroyed aquatic habitat putting many of these species at risk. Research on ecological flows of the Tennessee River and their tributaries [9] is examining how changes in climate, land cover, soil properties and physiography drive stream flow responses. Knight et al. [9] found basin characteristics explained over half of the variation in streamflow with daily temperature range, rock depth and geology being other co-variables. One of the most influential factors is regional climate variables-mean monthly precipitation, daily temperature range, January precipitation, and August temperature. The relationship between flow and aquatic ecology is complex and not yet well understood [12]. The TVA continues to monitor and use research findings as feedback loops to adaptively manage not only their lock and dam network but also the land and river uses throughout the Tennessee River basin.

Bighead and Silver Carp in the Tennessee River Have Invaded Kentucky Lake in Substantial Numbers
The silver carp (Hypophthalmichthys molitrix) (Figure 26), also known as the flying Asian carp [10], began migrating through the Mississippi River, Ohio River and into the Tennessee River and have now enter both the Kentucky and Barkley Lakes [12]. The carp escaped the Arkansas fish farms and began migrated up the Mississippi River system. The carp can jump above water and can grow to 23 kg. The carp were first introduced, with the approval of the Environmental Protection Agency (EPA) in the 1970s, to help consume algae in catfish farm ponds within Arkansas [12]. The carp remove the bottom of the food chain for indigenous species and displace the native species of filter feeding fish.
Harvesting the carp for food has been one of the most successful approaches to date ( Figure 27). Journal of Water Resource and Protection  Suski suggested "the carp do not displace native fishes and he is not aware of any displacement to date". Dr. Suski noted "that the Asian carp out-compete the native fish for food, and several species of fishes (particularly filter feeding fishes) have experienced reduced conditions, likely through competition" [13]. There are other carps (grass carp, black carp) but of less concern than bighead and silver carp.

Tennessee River Regional Trail System
Known as North America's Next Regional Trail System, the Tennessee River Line project [14] was started in 2016 and headquartered in Knoxville, Tennessee.
The Conservancy.
"The Tennessee River Line trail project was started to create a network of trails to paddle, hike and bike along the 652 river mile length of the Tennessee River. The project is now taking the next step, by signing the first batch of River Towns to participate in the project" [14]. The Tennessee River Line trail project

Conclusions
The Tennessee River and its series of locks and dams are owned by the U.S. federal government and jointly managed by TVA and USACE. The U.S. Coast Guard ( Figure 33) works closely with both agencies to assure reliable and safe navigation for commercial and recreation vessels and enforces maritime laws, marine safety and investigations of marine accidents [15]. The Coast Guard is also responsible for installation and maintenance of lights, buoys, and shoreline markers along 1280 km of the river's commercial channel.
With the construction of the Kentucky Dam on the Tennessee River water can be stored and released during droughts to maintain a minimum 2 m depth of water above the 2.7 m shipping channel. These water releases also increase the water level in the lower Mississippi River. During the 2012 drought, the USACE was able to add 1.2 m to the existing river water level which reduced the need for dredging. During major flooding events, between 1940s and 2011, the New Madrid floodway in Missouri did not have to be opened until 2011. The USACE was able to mitigate the flood impact by not releasing water from upstream reservoirs including the Kentucky Lake.