**2. Literature Review**

This section will discuss the importance of green infrastructures in attracting other uses. It will present four case studies of policies that turned watercourses into green infrastructures. It discusses land use change, the use of urban greenways and green corridors, threats to character change and the public perception of city character.

Some studies have shown the positive impact of existing natural and environmental facilities in achieving economic land use development [13,21–23]. Green amenities and urban greenways played a critical role in attracting communities and land use development. In the United States, residents prefer to live near parks and greenways, thus land use development has resulted from people's mobility to green amenities, such as urban greenways [24–26]. In Egypt, the local residents benefited from the existence of the urban greenway in linking their neighborhoods, promoting education and recreation, as well as preserving the natural environment and raising the awareness about its importance. In addition, greenways attract business, commercial and cultural uses when they intersect with residential areas [26].

People have strong feelings towards their natural environments. This social need is subject to change based on municipal decisions. Some policies have succeeded in guiding the compass towards environmentally and urbanely neglected areas, through making these areas safe and attractive urban areas that entice investments and population alike. The next sections will introduce four case studies; Cheonggyecheon, Seoul, South Korea; Los Angeles River, LA, USA; San Antonio Riverwalk, TX, USA; and Bartin River, Turkey.

In South Korea, the restoration of Cheonggyecheon stream came after more than 30 years of covering up the watercourse with concrete and an expressway. The stream was first converted into an elevated freeway project, which caused years of degraded, poor environmental conditions. Lastly, the Seoul mayor initiated a project to remove the elevated freeway and to restore the stream, providing an urban greenway [27,28]. This restoration gained the city economic and development revenues and created land use change. The restoration led to conversion of the residential land use into commercial and mixed land uses surrounding the greenway, while the residential uses shifted to farther distance with higher densities.

The Los Angeles River has witnessed another successful example in reviving the city character. This Los Angeles River was originally an alluvial river, crossing floodplain areas on which Los Angeles and other surrounding towns were built [29–31]. Until 1825, the river discharged into the sea. Later, the river way to the sea became muddy and blocked the river flow.

*Land* **2019**, *8*, 195

The waters flooded and spread all over the land adjacent to the river and filled the lowlands, creating lakes, swamps and ponds [32]. In 1913, the Los Angeles Aqueduct was opened. The river was the main source of water at that time, despite the fact that the water was shallow for most of the time except winter [29]. In the 1930s, frequent floods devastated the river, therefore, the mayor of Los Angeles, Frank L. Shaw (1877–1958), worked in cooperation with the US Army Corps of Engineers (USACE) on several measures to control and reduce floods. They worked on a project to cover the riverbed and its banks with concrete, and turned it into a canal intermediated with a small flow of water [31]. Channelizing the river led to the drying up of the river for nine months of the year. The conditions repeated until the 1950s, when the water was re-pumped into the canal with the industrial and residential discharge of gray water. In 1986, the Friends of the Los Angeles River (FoLAR) organization was established to revive the river and to restore habitat and public access to the river [30–33]. Later, the nonprofit group River LA (formerly, Los Angeles River Revitalization Corporation) announced in 2013 the goal of completing about 82km of greenway and bike path along the river by the end of 2023. This route is expected to be the main hub of a Linear park, in addition to providing an alternative transportation route through the city [33]. The USACE conducted a feasibility study on the river restoration project. They recommended a plan worth \$453 million for flood protection and ecosystem restoration for 600 acres [34].

The San Antonio Riverwalk presents one of the most successful walkway networks. The Riverwalk, located along the San Antonio River in Texas, is considered an important part of the urban fabric of the city. It is an attractive destination to local residents and tourists due to the lining of shops, restaurants and historical missions integrated with nature on both riverbanks [35,36].

A catastrophic flooding of the San Antonio River killed 50 people in 1921. To reduce the risk of flooding, a flood control plan was initiated including the construction of a dam at the source of San Antonio River, and the creation of a storm sewer by paving the bend of the river [37,38]. In 1926, the San Antonio Conservation Society protested against the plan of paving the sewer and prevented the implementation of the plan. In 1929, architect Robert Hugman (1902–1980), presented a plan to turn it into a Riverwalk surrounded by commercial development. Despite the much interest in the development and construction of the site, the architect and later mayor Mr. Jack White played a key role in enabling the San Antonio River Beautification Project through the idea of issuing bonds to raise funds to support the project in 1938 [37–39]. Congressman Maury Maverick, Mayor C. K. Quin (in office 1933-1942) and a group of citizens, headed by White began the site development [37–39].

During the successive decades, there have been improvements and expansions along the Riverwalk. The development incorporated several stages of expansions and improvements: 1968, 1981, 1988, 2009 and 2011. Now improvements and ecological controls include the long-distance walkways, cycling trails and rowing trails, which allowed accessible touristic experiences [37–39].

In Turkey, a similar case found that the Bartın River pertained a significant potential for creating a preserved land use balance to promote future urban development. It was foreseen to support the environmental health and aesthetic character in the city. The preservation will mitigate food and flood risks on the river corridor [40].

Policies turned Cheonggyecheon in Seoul, the San Antonio River and the Los Angeles River into effective greenways and green corridors that improved the green infrastructure of their cities. Restoring the Seoul stream into a greenway was considered as an important policy to reintroduce nature to the city which led to a reduction of the urban heat island effect by as much as eight degrees centigrade, in comparison to nearby paved roadway conditions according to summertime measurements [41]. To promote a more ecofriendly urban design, it brought improvements in water quality as well as the creation of a natural habitat [42]. In addition, it restored the history and culture of the region and revitalized Seoul's economy. As traffic decreased, air quality improved in the created linear park along the stream (greenway) with landscaping, good walking facilities and plenty of street furniture. It slowly became an attractive destination for both residents and businesses, which led to land use change and economic development [27,28].

One of the most important ecological issues highlighted over the last decades is turning green corridors into culverts. Policies now focus on preventing the coverage of natural waterways by promoting the transformation of these structures, and restoring urban waterways back into more natural courses [6,43]. Many countries of the world have taken the approach of restoration of urban waterways as an opportunity to reduce the shortage of natural open spaces and enhance the wellbeing of the local communities through affording linear recreational areas within the cities [44].

Urban greenways have played an important role in the promotion and the development of urban and suburban environments. They provided the most needed natural corridors inside the urban areas, mitigated the loss of natural spaces which are affected by the urban expansion and constituted the primary resistant form to the built environment [26,45,46]. Greenways approach aims to protect nature which balances between the conservation and the growth through creating livable environments and maintaining open spaces. They help maintain biological diversity, protect water resources, conserve soils, improve air quality, reduce pollution, support recreation, enhance community and cultural cohesion, provide species migration routes during climate or seasonal change, manage water runoff, contribute to aesthetic qualities, enhance economic values, diversify recreational opportunities through activities and protect natural character [47–51]. Greenways could thus be considered lines of opportunity; they contribute to many ecological and societal values, reviving cities and preserving character [45].

The 'town character' or 'city character' terms often referred to the sum of the distinctive features and elements that make the town unique. The character is associated with environmental features, and with the response to the environmental and social aspects of the town, by which people judge the suitability of changes in their surrounding environment [52]. The concept of city character is substantially associated with deep emotional attachment between individuals and the city, especially peacefulness and enjoyment [53].

Sometimes, local residents feel the loss of their authentic and significant environment's character due to the changes and developments in their cities [54]. Therefore, it is necessary to preserve the valued familiar environmental features because of their importance in preserving the psychological and personal aspects as they contribute to the community perception of the authentic, significant, local and general city character [52,55].

The elements of the natural environment participate in shaping place character. The hydrological, ecological, geological, vegetation and landform features are significant features in creating the distinctive visual atributes of the place [54]. Places that have successfully integrated the natural features of water bodies, vegetation and topography maintain the natural character of the place and gain distinctive visual links [54,56].

Altman and Zube [57] show that the transformation of the undefined space to what we call a "place" comes from the transformation of the mere geographical environment by people who use it, adjust it, or give it a symbolic value, while the word 'character' indicates the set of qualities and features that identify one thing or person from others. Place character can be illustrated by aggregation of the special place features, which give their place the unique identity [54]. It is the combination of the distinctive elements of the place that give it a unique value and a special identity. These elements and features make the sense and the ambience of the place [58,59]. All the places have distinct characters, such as people who have their unique personalities that vary from one person to another [60]. However, the place character can be expressed through the unique aggregation of the socio-physical features that distinguish the environments from one to another [34,60–62]. Place character can be simply depicted as the 'sense' and the 'atmosphere' of a place [54].

The perception of town character by the public was examined by Green who focused on community perception to explore the notion of town character based on the community perspective of the small coastal town of Byron Bay, New South Wales, Australia [52–54]. Green found that there is a relationship between environmental features, their associated meanings and the perception of the character of the town. The positive meanings were distinctiveness, pleasantness, charm, familiarity, friendliness, openness, liveliness and safety. The negative meanings were boredom, ugliness, lack of charm, lack of stimulation, monotony, unpleasantness and being ordinary [52].

In his book, *The Image of the City*, Kevin Lynch (1960) reached a conclusion that places are experienced in relation to their surroundings, the events that lead to them and past experienced memories. Citizens experience the city through the experience of the small parts, niches and events that together feed the citizen with the memories and meanings [63].

Literature summary. Despite the fact that municipalities believe that good planning will lead to better economic returns, this is not always reached by the turning of land uses to successful economic and commercial uses. Land use development policies have to improve, manage and increase the effectiveness of human activities associated with land uses, with direct awareness of the importance of green open spaces and natural environmental assets [9,12,13]. Problems may be exacerbated by the lack of awareness of the social needs and problems faced by communities and affected by decisions on the community environment [64]. Some policies focused on a scope targeting environmentally and urbanely neglected areas through making these areas safe and attractive urban areas that attract investments and population alike, such as the case of Seoul, Cheonggyecheon; Riverwalk, San Antonio and the LA River project. In most of these cases the goal was not only to enhance land use, but also to sustain a town/city character by preserving a natural asset and implementing through it some purposeful planning strategies.

The tangible and physical features in the city contribute significantly to the formation of the mental images, deepen emotional attachments between individuals and the city and facilitate the process of cognition and sensory connection [53,54]. Some studies examined the city character at the scale of cities or small towns through studying the community perception [52–65]. Other studies examined the city character at the microscale, through studying the transformation of the urban identity, where the physical characteristics of the built environment are assessed [31]. But no studies assessed the impact of land use change on the city character or the impact of demolishing natural features and green corridors on converting the city character. Previous studies analyzed changes in urban identity through monitoring urban transformations [55]. They monitored morphological changes through analyzing street patterns, urban blocks and land uses [66]. Some focused on lot-based changes and redevelopment impacts by acquiring data on building permits and land use changes [67]. Some studies focused on the public perception of change independently to show the importance of integrating the stream corridor into the urban greenway plan [68].

Land use development, together with morphological foot prints, are a dynamic form of shaping and reshaping of the city. The growth of populations is physically marked by the traces of both morphological form and shape development in relation to scale and the land use proportions and land use changes. The impact of watercourses dynamics on urban morphology and land use change are major components in shaping the image of the city. Other intangible factors are sensual in the perception of people. Both the sensual and the tangible components are continually shaped and constantly affect the character.
