The Evaluation of Urban Renewal Waterfront Development: the Case of the Sava Riverfront in Belgrade, Serbia

sustainability

Article The Evaluation of Urban Renewal Waterfront Development: The Case of the Sava Riverfront in Belgrade, Serbia

Aleksandra Djukić 1 , Jelena Marić 1, Branislav Antonić 1 , Vladimir Kovaˇc 1,*, Jugoslav Joković 2 and Nikola Dinkić 2 1 Faculty of Architecture, University of Belgrade, Bulevar kralja Aleksandra 73/II, 11000 Belgrade, Serbia; [email protected] (A.D.); [email protected] (J.M.); [email protected] (B.A.) 2 Faculty of Electronic Engineering, University of Niš, Aleksandra Medvedeva 14, 18000 Niš, Serbia; [email protected] (J.J.); [email protected] (N.D.) * Correspondence: [email protected]

Received: 9 July 2020; Accepted: 10 August 2020; Published: 15 August 2020

Abstract: Belgrade is the only capital in the world at the confluence of two major international rivers navigable for global shipment—the Danube and the Sava River. However, it was only after the unification of all riversides within Yugoslavia in 1918 that Belgrade started to develop its riverfront; initially, as green recreation areas during the socialist era. Since the post-socialist transition, this trajectory has sharply changed in order to create new urban nodes along the riverfront. The best example is the newest project of the urban renewal of waterfront development at the Sava River, the “Belgrade Waterfront Project.” This mega-project has sparked a lot of attention. The aim of this research is to present, evaluate, and spatially determine this attention before and after the project inauguration. This observational study is conducted by using two methods from social discourse: a survey, as a traditional method, and analysis based on social network data (Twitter) as a newer, “smarter” one. Comparing and mapping their results, this research offers recommendations on how to harmonize and modernize the development of this crucial potential of Belgrade.

Keywords: social media; survey; riverfront development; modernist urbanism; post-socialist urban transformation

1. Introduction: The Essence of Waterfront Development Waterfront (re)development has been greeted as a panacea for newer urban evolution in post-industrial cities for the last 40 years [1]. This was noticed even at the beginning of this phenomenon, during the early transition from the industrial phase of urbanization in the late twentieth century [2]. Many cities have found a new ground for such development among the former industrial complexes and docklands, ideally located along their inner waterfronts [3,4]. In recent years, this type of urban project has become a new “normality” for tracing the future of contemporary cities at the global level [5]. Moreover, many mega-projects of new waterfronts that have emerged across the world have been praised as role models for modern urban development. Even cities piled with severe socio-economic problems, such as Detroit whose demographic loss in the last half of a century was more than 50% [6], have got new waterfront developments, such as the new mixed-use project on the site of former “Stroh” brewery in the city riverfront [7]. Europe, with many historic industrial cities, has many successful examples of city recovery managed through the waterfront-led regeneration. Bilbao in Northern Spain is probably the most famous for its outstanding culture-based waterfront regeneration, considering new Guggenheim Museum and the popular “Bilbao Eﬀect.” which has further inﬂuenced the revitalization of the local art and culture scene [8].

Sustainability 2020, 12, 6620; doi:10.3390/su12166620 www.mdpi.com/journal/sustainability Sustainability 2020, 12, 6620 2 of 16

The significance of waterfront development can be observed in different ways. First, the former unused or insufficiently used industrial and/or transportation space is an economical and ecological burden for city authorities in the form of brownfield [9,10]. Furthermore, their successful transformation in new and vibrant urban nodes can be observed as a benefit regarding both physical and functional ways; the related changes can be noticed through the different personal perception of these urban spaces, as well as in the reconfiguration of existing social ties within them [11,12]. Finally, if the former structures in a waterfront area carry the significance of cultural heritage, the process of their transformation into new urban hubs can be even more complex [13–15]. This complexity of waterfront redevelopments is especially reflected in its influence on society. Newly established waterfront zones have become increasingly attached to newcomer elite groups since the first examples of waterfront development [3]. This contradiction of prospective waterfront development can be noticed even in the early stages of their transformation [16]. Typically, there is a gap in the vision of the waterfront transformation between city authorities, with elite groups in the background, and the local population, who are represented through activists’ initiatives [17]. Such tensions are more often seen in the global cities that have faced the recent turbulences and socio-political transition, such as many major cities in post-socialist countries in the European east [18,19]. The socio-economical transition from a socialist to a capitalist state system has made a deep impact on the pioneer waterfront projects during the 1990s, thus their regeneration process has differed more greatly than the Western counterparts’ [20]. Preliminary research concludes that the governments of the main post-socialist cities do not have a clear vision of the waterfront (re)development. These new waterfront projects are usually managed from one project to another, thus making the waterfront urban fabric more fragmented [20,21]. Nevertheless, many large and physically striking projects were built along the seafronts and riverfront of cities in post-socialist Europe, such as Okhta Center in St. Petersburg, Russia [22], Nowy Port in Gdansk, Poland [23], or Millennium City Center in Budapest, Hungary [21]. In relation to these evident social tensions in waterfront projects [24], the aim of this research is to examine current public opinion and the uses of the Belgrade waterfront, emphasizing the impact of the newest, post-socialist projects on its users. This is fundamentally a definition of sentiment analysis [25]. However, it is adjusted to reflect public opinion in the urban space, which is a new field of research [26]. Two methods used from a social research context were thereby customized to enable this approach—a survey as a traditional method and analysis based on data from a social network (Twitter) as a newer, “smarter” one. Tweets are data resources for extracting opinions and feelings in the real-time and the text data in tweets are used in research to analyze sentiments and obtain valuable results which cannot be provided otherwise [27,28]. Through comparing and mapping their results, this research offers recommendations on how to socially harmonize and eventually modernize the development of the Belgrade waterfronts as a crucial potential for the city’s future.

2. Belgrade: The Timeline of Modern Riverfront Development Although Belgrade is the only capital that lies on two big rivers, the Danube and Sava [29], these rivers have influenced the formation of the present-day city in an unusual way. The critical period of the Belgrade genesis was early modernity, from the late 17th to early 20th century. During this period, both rivers represented borders between two empires: the Habsburg Empire in the north and Ottoman Empire in the south. These empires were totally different regarding cultural, political, and religious realms that were in constant mutual conflict, which made the borders on the Danube and Sava Rivers a real military frontier [30]. Consequently, Belgrade retreated from both rivers to the ridge between them, as some kind of a “supervisor” on both riversides, which mainly consisted of marshlands. This “uphill” position of the city has been preserved until today; Belgrade’s inner center is still on the top of the ridge above the confluence of the Sava into the Danube. Only a relatively short Sava riverfront with port facilities in the Savamala Quarter (see: Figure1) was formed during this period [31]. Sustainability 2020, 12, x FOR PEER REVIEW 3 of 17 short Sava riverfront with port facilities in the Savamala Quarter (see: Figure 1) was formed during this period [31]. A new impulse for the Belgrade waterfront on three riversides waited for the moment of the unification of all of the city riversides under one unity. This happened with the end of World War I in late 1918, with the formation of the State of Slovenes, Croats, and Serbs, known as Yugoslavia after 1929 [32]. The capital of this young country immediately spotted its riverfronts as a spatial potential to enlarge its territory, which was clearly outlined in the first general urban plan after the war, from 1922 [33]. However, only a few of the measures and projects proposed by the plan were implemented; the main ones considered a new Belgrade port on the Danube side of the city center, with the first city bridge across the Danube and Branko Bridge (Serb. Brankov most) on the Sava River [33] (See: Figure 1). The present-day riverfront along the Danube and Sava (Figure 1) was shaped in the period after World War II, during socialist Yugoslavia (1945–1991). Most of the efforts were given to create New Belgrade (see: Figure 1), a new modernist core city within Belgrade, across the Sava River from Old Belgrade [34]. In line with the contemporary functionalist style, this part of the city was built in a super-blocks structure—open blocks with mass housing as a dominant urban function and a lot of greenery around it. Several blocks were dedicated to the most important institutions of socialist Yugoslavia, such as the Building of Federal Executive Council (today known as the Palace of Serbia) [35].Sustainability New Belgrade2020, 12, 6620 waterfronts on the Danube and Sava followed these modernist tenets; they 3were of 16 created as a pedestrian quay “inserted” between the river and green riverside belt.

Figure 1. Waterfront parts in present-day Belgrade with the most important quarters and structure (author: V. V. Kovaˇc2020).Kovač 2020).

TheA new same impulse principle for was the Belgradeused for the waterfront free waterfront on three areas riversides in Old waitedBelgrade for on the the moment eastern ofbank the ofunification the Sava ofRiver, all of such the cityas Ada riversides Ciganlija under (see: one Figu unity.re 1). This This happened former river with island the end was of Worldartificially War connectedI in late 1918, with with the mainland the formation and gradually of the State transforme of Slovenes,d into Croats, the largest and Serbs, sport and known recreation as Yugoslavia area of theafter city 1929 [31]. [32 However,]. The capital most ofof thisthe Old young Belgrade country waterfront immediately was spotted“frozen” its in riverfrontsthe state before as a spatialWorld Warpotential II, neglected to enlarge and its dilapidated territory, which for several was clearly decades. outlined This view in the was first radically general changed urban plan in the after 1980s, the duringwar, from late 1922 socialism, [33]. However,with the in onlyternational a few of rise the of measures post-modernist and projects awareness proposed of the byvalues the planof the were old urbanimplemented; fabric and the traditional main ones city. considered This new a movement new Belgrade was port capitalized on the Danubein the first side big of redevelopment the city center, projectwith the of firstthe citycentral bridge part acrossof the theBelgrade Danube wate andrfront, Branko located Bridge between (Serb. theBrankov New Belgrade most) on theand SavaOld River [33] (See: Figure1). The present-day riverfront along the Danube and Sava (Figure1) was shaped in the period after World War II, during socialist Yugoslavia (1945–1991). Most of the efforts were given to create New Belgrade (see: Figure1), a new modernist core city within Belgrade, across the Sava River from Old Belgrade [34]. In line with the contemporary functionalist style, this part of the city was built in a super-blocks structure—open blocks with mass housing as a dominant urban function and a lot of greenery around it. Several blocks were dedicated to the most important institutions of socialist Yugoslavia, such as the Building of Federal Executive Council (today known as the Palace of Serbia) [35]. New Belgrade waterfronts on the Danube and Sava followed these modernist tenets; they were created as a pedestrian quay “inserted” between the river and green riverside belt. The same principle was used for the free waterfront areas in Old Belgrade on the eastern bank of the Sava River, such as Ada Ciganlija (see: Figure1). This former river island was artificially connected with the mainland and gradually transformed into the largest sport and recreation area of the city [31]. However, most of the Old Belgrade waterfront was “frozen” in the state before World War II, neglected and dilapidated for several decades. This view was radically changed in the 1980s, during late socialism, with the international rise of post-modernist awareness of the values of the old urban fabric and traditional city. This new movement was capitalized in the first big redevelopment project of the central part of the Belgrade waterfront, located between the New Belgrade and Old Sustainability 2020, 12, x FOR PEER REVIEW 4 of 17 Sustainability 2020, 12, 6620 4 of 16 Belgrade centers, the International Competition for the New Belgrade Urban Structure Improvement (1984–1986) [33]. BelgradeThe centers,turbulent the 1990s International prevented Competition any kind forof thecompetition New Belgrade implementation. Urban Structure Nevertheless, Improvement the (1984–1986)post-socialist [33 transition]. has brought new, private “players” in the redevelopment of the central part of theThe Belgrade turbulent waterfront. 1990s prevented Their any interests kind of were competition completely implementation. different in Nevertheless, their essence the due post-socialist to a new, transitioncapitalist hasenvironment. brought new, The private conditions “players” of ina themarket-led redevelopment economy of theimmediately central part refocused of the Belgrade their waterfront.attention from Their the interests peripheral were parts completely of the differentBelgrade in riverfront their essence to more due tocentral a new, locations capitalist “entrenched” environment. Thewith conditions a post-industrial of a market-led decline economyafter the fall immediately of socialism refocused and ripe their for attention urban renewal from the [36]. peripheral In such partsway, ofBelgrade the Belgrade riverfront riverfront visions to more were central joined locations to “entrenched”a myriad of with postponed a post-industrial post-industrial decline after urban the fallredevelopment of socialism and attempts, ripe for plans, urban and renewal projects, [36]. typica In suchl for way, young Belgrade post-socialist riverfront visionssocieties were in the joined eastern to a myriadhalf of Europe of postponed [37]. post-industrial urban redevelopment attempts, plans, and projects, typical for young post-socialistThe first societies attempts in the at eastern urban half redevelopment of Europe [37]. started in the 1990s with plans and open competitionsThe first attemptsfor the so-called at urban “Belgrade redevelopment on Water” started project in the [36]. 1990s However, with plans they and did open not competitions include the forissue the of so-called land ownership, “Belgrade as on a re Water”quirement project for [ 36the]. However,project implementa they did nottion, include which theled issueto a series of land of ownership,development as issues a requirement [37]. On forthe the other project hand, implementation, new private investors which led rediscovered to a series ofthe development potential of issuesriverfront [37]. locations On the other in Old hand, Belgrade, new private gradually investors taking rediscovered the initiative the potential for (re)development of riverfront locations projects infrom Old the Belgrade, public graduallysector [38]. taking New theprojects initiative firstly for aimed (re)development at the less projectsprominent from locations the public of sectorindustrial [38]. Newand projectstransport firstly brownfield, aimed at thelike less the prominent spontaneous locations urba ofn industrialregeneration and of transport industrial brownfield, heritage like called the spontaneous“Beton Hala.” urban The regenerationother redevelopment of industrial mixed-use heritage projects called “Beton like “Marina Hala”. TheDorć otherol” have redevelopment been more mixed-usecontroversial. projects These like projects, “Marina authored Dorćol”have by Arch. been Daniel more Libeskind controversial. and the These “Beko” projects, project authored by Arch. by Arch.Zaha Hadid, Daniel have Libeskind had the and implicatio the “Beko”ns of project “starchitecture” by Arch. Zaha projects Hadid, confined have within had the a implicationsstrict neoliberal of “starchitecture”context, thus excluding projects confineda noticeable within social a strict dimensio neoliberaln [39]. context, It should thus be excluding noted that a noticeable not all of socialthese dimensionprojects were [39 ].only It should economically be noted driven; that not some all of theseof them projects were were more only prone economically to the social driven; and somecultural of themrevitalization were more of pronethe old to theurban social fabric and culturalalong the revitalization rivers, such of theas the old urbanregeneration fabric alongof the the historic rivers, suchSavamala as the Quarter, regeneration today ofknown the historic as the Savamala Savamala Cultural Quarter, District today known[31]. as the Savamala Cultural District [31]. However,However, thethe last last and and biggest biggest of them,of them, the “Belgradethe “Belgrade Waterfront Waterfront Project” Project” (henceforth: (henceforth: BW Project), BW hasProject), been inhas progress been in since progress 2012, withsince on-site 2012, constructionwith on-site fromconstruction 2015 (Figure from2). 2015 This ongoing(Figure 2). project This occupiesongoing theproject large occupies area of the the main large railway area andof the bus main stations railway of Belgrade and bus with stations supplementary of Belgrade technical with facilities.supplementary Both technical stations arefacilities. in the Both process stations of reallocation. are in the process Due to of its reallocation. size, physical Due appearance, to its size, andphysical general appearance, importance and for general the city, importance this mega-project for the hascity, received this mega-project a lot of public has andreceived professional a lot of attentionpublic and with professional diverse opinions, attention thus with becoming diverse the opinions, most important thus becoming and most the controversial most important project and in Belgrade.most controversial It has proved project to be ain challenge Belgrade. for theIt has whole proved city development to be a challenge [40]. Nevertheless, for the whole it certainly city showsdevelopment the new [40]. developmental Nevertheless, trajectory it certainly of Belgrade shows the as new a whole developmental [41]. trajectory of Belgrade as a whole [41].

FigureFigure 2. 2.TheThe Belgrade Belgrade Waterfront Waterfront Projec Projectt (BWP) (BWP) in progress; in progress; thethe Savam Savamalaala District District is on is onthethe left. left. BothBoth city city areas areas are are mapped mapped in inFigure Figure 1 (author:1 (author: B. B.Antoni Antoni´c2018).ć 2018).

3. Methods and Materials Sustainability 2020, 12, 6620 5 of 16

3. Methods and Materials This research was organized into two major steps. The first one concerned the aforementioned historic development of the Belgrade waterfront. The focus was on urban development after World War II, comprising both socialist and post-socialist phases. The second step consisted of two analyses: Analysis A: A survey that intended to gain an overview of the opinion of the local population about the ongoing transformation of the Sava and Danube riverfronts. It used a traditional method to obtain qualitative data but was carried out using modern technologies through an e-questionnaire. The survey with an e-questionnaire was conducted among the Belgrade population in July and August of 2018. In total, 281 respondents participated. It included eleven thematic semi-open questions relating to the opinion of the local population about the ongoing transformation of the Sava and Danube riverfronts. Before them, three introductory questions were given to distinguish the structure of respondents: their gender, age, and the living area in Belgrade. Analysis B: The second analysis was quantitative and included “smart” and interactive technologies that promote the formation and sharing of information, ideas, and interests. It was the analysis of social media—Twitter. The use of tweets has been already confirmed as adequate to extract the geospatial data important for urban development [42]. The aim of this section was thereby tracking and measuring the intensity of users in the monitored territory of the Sava waterfront, with the testing of their latest behavioral patterns, as well as tracing the most attractive routes along this waterfront. Both analyses have certain limitations, therefore the specific measures were undertaken to minimize their impact. The first one used an e-questionnaire, distributed through social media channels, with the respect of privacy and respondent anonymity. The option of an e-questionnaire is more suitable for younger generations. Therefore, the oldest contingent of the population (above 65 years) was successfully included in the survey through in-person support for completing the e-questionnaire. Nevertheless, this population contingent was a bit under-represented (9%). The second analysis opted for just one representative of social media to adequately cover all content regarding the proposed analysis. This was legitimized through the selection of Twitter because it is one of the most popular data sources for such research [43,44] with its transparency in an open network, which allows access to the information published through its platform. Microblog data like Twitter offer a varied kind of different information because its users post real-time reactions to every item. The comparison and mapping of the results from these quantitative and qualitative analyses and the further link with the historic context of the research problem bring new insights in the form of recommendations regarding the very complex issue of waterfront development in Belgrade.

4. Results: Regarding the Current Use of Belgrade Waterfronts

4.1. Research A: Survey with Questionnaire As it was mentioned in the previous section, the first three questions in the questionnaire were the introductory ones about a respondent profile. The results from these questions roughly concur with general figures for the Belgrade City:

Female respondents were slightly more prevalent than males (56% and 44%, respectively); • The place of living pointed to most respondents living in Old Belgrade (60%). The next most • common was New Belgrade at 27%. Less frequent answers were “Zemun” and Trans-Danube/“the Third Belgrade” (8.5% and 4.3%, respectively); Age groups were rather evenly distributed but with a slight prevalence of younger generations • from 25 to 34 years (32%). The other age groups were distributed as follows: 16–24 (24%), 35–49 (22%), 50–64 (13%), and above 65 years (9%).

The ﬁrst part of the questionnaire consisted of four thematic questions intended to clarify the general character of respondents’ use of the city riverfront. The ﬁrst question was a key to continue to the survey, and 95% of respondents answered positively and thus continued to the next questions. Sustainability 2020, 12, x FOR PEER REVIEW 6 of 17

SustainabilityEven those 2020 people, 12, x FOR who PEER did REVIEW not use the riverfronts presented at 5%. Their participation in this survey6 of 17 Sustainabilityshows that2020 , 12a ,general 6620 interest in the city riverfront development is not limited to just6 ofthose 16 EvenBelgradians those people who whoactively did notuse usethe thecity riverfronts waterfront; presented the other at ones5%. Their are also participation interested in in this waterfront survey Evenshowsdevelopment those that people a duegeneral who to didits interest significance not use in the the riverfrontsfor city the riverfentire presentedront city . developmentThe at ov 5%.erall Their majority is participation not limitedof respondents into this just survey (>95%),those showsBelgradianshowever, that a actively general who actively interestused Belgrade use in the the city waterfrontscity riverfront waterfront; (Figure development the 3 ,other left). isAlmostones not are limited one also-sixth to interested just of thoseall of in Belgradiansthem waterfront used the whodevelopmentriverfront actively daily, use due the and to city its the waterfront;significance majority of the forthem other the (44%) entire ones stated are city. also theyThe interested overallwalked majority inalong waterfront the of rivers respondents development several times(>95%), due per tohowever,month. its signiﬁcance actively for used the Belgrade entire city. waterfronts The overall (Figure majority 3, left). of respondents Almost one-sixth (>95%), of all however, of themactively used the usedriverfront Belgrade daily, waterfronts and the majority (Figure of3, left).them Almost(44%) st one-sixthated they walked of all of along them the used rivers the riverfrontseveral times daily, per andmonth. the majority of them (44%) stated they walked along the rivers several times per month.

Figure 3. The thematic questions No. 2 (left) and No. 3 (right) (author: B. Antonić 2018). Figure 3. The thematic questions No. 2 (left) and No. 3 (right) (author: B. Antonić2018). ParticipantsFigure 3. mainlyThe thematic used questions the waterfront No. 2 (left area) and with No. 3 a (right partner) (author: or with B. Antoni friendsć 2018). (36% and 35%, respectivelyParticipants, Figure mainly 3, used right the). This waterfront confirms area that with the a partnerBelgrade or riverfront with friends pla (36%ys an and important 35%, respectively,socializingParticipants Figure role formainly3, right). the localused This population.the confirms waterfront that This the area is Belgrade indirectly with a riverfront partner repeate ord plays inwith the an friendsnext important question (36% socializing and (Figure 35%, 4 , rolerespectively,left for). theThe localkey Figure population.reasons 3, forright). using This This is the indirectly Belgradeconfirms repeated waterfrontthat the in theBelgrade include next question theriverfront socially (Figure -playsresponsive4, left).an important The groups key of reasonssocializingactivities, for using role such for the as theBelgradeentertainment local population. waterfront (46% include )This and is recreation theindirectly socially-responsive (37%).repeated The in othergroupsthe next options, of question activities, which (Figure such can as 4, be entertainmentleft).described The key as (46%) reasons a daily and forroutine recreation using rather the (37%). Belgrade than The a other personalwate options,rfront desire, include which were canthe significantly be socially-responsive described as less a daily present groups routine in of the ratheractivities,responses. than asuch personal as entertainment desire, were significantly(46%) and lessrecreation present (37%). in the responses.The other options, which can be described as a daily routine rather than a personal desire, were significantly less present in the responses.

Figure 4. The thematic questions No. 4 (left) and No. 5 (right) (author: B. Antonić2018). Figure 4. The thematic questions No. 4 (left) and No. 5 (right) (author: B. Antonić 2018). The second block of thematic questions pertained to the (different) patterns of use of the Sava and theThe Danube Figuresecond riverfronts. 4. block The thematic of Thethematic fifthquestions questionquestions No. 4 made ( leftpertain) and a distinctioned No. to 5 the(right (different) between) (author: these B.patterns Antoni riverfronts ćof 2018). use regarding of the Sava respondentand the useDanube (Figure riverfronts.4, right). Ada The Ciganlija, fifth question the main ma andde bya distinction far the largest between recreation these green riverfronts area alongregardingThe the rivers,second respondent was block given of use thematic separately. (Figure questions4,The right results). Adapertained show Cigan that lija,to thethe the (different) Sava main Riverfront and patternsby far was the of morelargest use of used recreationthe with Sava orandgreen without the area Danube Ada along Ciganlija riverfronts.the rivers included, wasThe (50% givenfifth and separately.question 37%, respectively). made The resultsa distinction Nevertheless, show thatbetween morethe Sava thanthese Riverfront one-quarter riverfronts was ofregarding allmore respondents used respondent with mainlyor without use used (Figure Ada the Ciganlija Danube4, right). riverfront, includedAda Ciganlija, (50% and more andthe main37%, than respectively).and one-fifth by far used the Nevertheless, largest both riverfronts recreation more equally.greenthan areaone This- quaralong distributionter the of rivers, all arespondentsffi rmativelywas given mainly confirms separately. use thatd Thethe di ff Danuberesultserent parts show riverfront of that the ,theBelgrade and Sava more Riverfront riverfront than one arewas-fifth attractivemoreused used both to users.with riverfronts or without equally Ada. Ci Thisganlija distribution included affirmatively(50% and 37%, confirms respectively). that different Nevertheless, parts more of the thanBelgradeBoth one-quarter riverfronts riverfront of are allare not respondentsattractive “monoliths” to usersmainly by use. used patterns the yet.Danube Many riverfront, parts of the and riverfronts more than are one-fifth specific byused their bothBoth development, riverfronts riverfronts and equally. are their not influence“monThis distributionoliths” on users by use affirmatively di ff patternsers greatly yet. confirms (Figure Many 5 partsthat). In different the of case the riverfronts ofparts the Savaof the are (FigureBelgradespecific5, left), riverfrontby their New development Belgrade are attractive Quay, and to (48%) users. their is mostinfluence used. on For users the Danubediffers greatly (Figure (Figure5, right), 5). it In is Zemunthe case of (37%),the BothSava although (Figureriverfronts answers 5, left are were), Newnot more “monoliths” Belgrade dispersed. Quay by However, (48%)use pa istterns most responses used.yet. Many toFor both the parts questionsDanube of the ( clearlyFigure riverfronts indicate5, right are), it thatspecificis the Zemun parts by their (37%), of the development, although waterfronts answers and located their were in influence Old more Belgrade dispersed.on users are differs not However, the greatly most responses used (Figure ones, to5). despite bothIn the questions case their of centraltheclearly Sava position indicate(Figure (Figure 5,that left), the5). New parts Belgrade of the waterfronts Quay (48%) located is most in used.Old Belgrade For the Danube are not the(Figure most 5, used right), ones it , isdespite Zemun their (37%), central although position answers (Figure were 5). more dispersed. However, responses to both questions clearly indicate that the parts of the waterfronts located in Old Belgrade are not the most used ones, despite their central position (Figure 5). Sustainability 2020, 12, x FOR PEER REVIEW 7 of 17 SustainabilitySustainability2020 2020,,12 12,, 6620x FOR PEER REVIEW 77 ofof 1617

FigureFigure 5. 5.The The thematic thematic questions questions No. No. 6 6 ( left(left)) and and No. No. 7 7 ( right(right)) (author: (author: B. B. Antoni´c2018). Antonić 2018). Figure 5. The thematic questions No. 6 (left) and No. 7 (right) (author: B. Antonić 2018). The last two questions in this question block were connected to the quality evaluation of the The last two questions in this question block were connected to the quality evaluation of the spatiallyspatiallyThe related lastrelated two elements elements questions of of thein the this Belgrade Belgrade question riverfront riverfront block were (Figure (Figure connected6). 6). The The eighth toeighth the question qualityquestion evaluation pertained pertained toof to thethe the spatiallyspatiallyspatially relatedrelated related reasons elementsreasons that that of are the are critical Belgrade critical for for personalriverfront person decisionsal (Figure decisions 6). and andThe preferences preferenceseighth question toward toward pertained a certain a certain part to partthe of thespatiallyof Belgradethe Belgraderelated waterfront. reasons waterfront. The that most are The critical frequent most for option personfrequent wasal related decisionsoption to thewasand urban-planning preferencesrelated to towardthe level—accessibility urban-planning a certain part (46%oflevel—accessibility the answers), Belgrade followed waterfront. (46% by answers), the choicesThe followedmost from thefrequent by urban-design the choicesoption ﬁeld—pavementfromwas therelated urban-design to and the path field—pavementurban-planning quality (31%), andlevel—accessibilityand the path quality quality of greenery(31%), (46% andanswers), (28%). the quality followed of greenery by the choices(28%). from the urban-design field—pavement and path quality (31%), and the quality of greenery (28%).

FigureFigure 6. 6.The The thematic thematic questions questions No. No. 8 8 ( left(left)) and and No. No. 9 9 ( right(right)) (author: (author: B. B. Antonić2018). Antonić 2018). Figure 6. The thematic questions No. 8 (left) and No. 9 (right) (author: B. Antonić 2018). ResponseResponse ratioratio inin thethe previous question question was was more more or or less less expected. expected. Thus, Thus, the the next next question question was wasrelated relatedResponse to the to the ratioissue issue in of the ofurban urbanprevious landmarks landmarks question in in was the the moreBe Belgradelgrade or less waterfront, expected. whichThus, the areare next alsoalso recognizablequestion recognizable was physicalrelatedphysical to elements elementsthe issue in theinof the urbanurban urban fabriclandmarks fabric but have but in athehave deeper, Be algrade psychologicaldeeper, waterfront, psychological meaning; which meaning; theyare helpalso inrecognizablethey individual help in orientationphysicalindividual elements in orientation urban spacein the in and urbanurban thereby spacefabric define and but anthereby have environment a define deeper, asan familiarpsychologicalenvironment or unfamiliar asmeaning; familiar [45]. theyor The unfamiliar analysishelp in showsindividual[45]. The that analysis orientation the most shows important in urbanthat the landmarksspace most and important thereby for respondents landmarks define an were environmentfor respondents the “Jugoslavija” as familiarwere the Hotel or “Jugoslavija” unfamiliar (47%) in Zemun[45].Hotel The (47%) and analysis Kalemegdan in Zemun shows andFortress that Kalemegdan the (41%) most inimportant centralFortress Belgrade landmarks(41%) in (Figure central for 7respondents ).Belgrade The first (Figure result were generally the7). The “Jugoslavija” first concurs result withHotelgenerally the (47%) significance concurs in Zemun with of and the the DanubeKalemegdan significance riverfront Fortress of in the Zemun. (41%) Danube in In central contrast, riverfront Belgrade the surroundingin (FigureZemun. 7). In riverfront The contrast, first result parts the aroundgenerallysurrounding the concurs Kalemegdan riverfront with Fortress,theparts significance around which is the aof monument theKale Danubemegdan of extraordinary riverfrontFortress, inwhich nationalZemun. is importance, aIn monumentcontrast, were the of notsurroundingextraordinary the first choices riverfront national by respondents. importance, parts around were thenot theKale firstmegdan choices Fortress, by respondents. which is a monument of extraordinaryThe option national that got importance, the minimal were support not bythe respondents first choices in by the respondents. previous question—new towers in the BW Project—was somehow an overture in the last block of two questions. It concerned this project in progress, which is certainly the largest one along the entire riverfront in Belgrade. The first question was more related to the new promenade along the Sava River, in front of the new towers (Figure2). The answers about the general affinity toward the promenade were rather divided by respondents (Figure8, left), but the relative majority of respondents (42%) appreciated the new development. In the last question of the survey, which closely connected the promenade with the BW Project, to a large extent the attitude of respondents was a bit different (Figure8, right). While the majority of respondents did not walk more often along the Sava River after the completion of the promenade in the front of the project, a sizable minority did (23%). Sustainability 2020, 12, x FOR PEER REVIEW 8 of 17

Sustainability 2020, 12, 6620 8 of 16 Sustainability 2020, 12, x FOR PEER REVIEW 8 of 17

Figure 7. The characteristic parts of the Sava and the Danube riverfronts in the Belgrade urban area (author: V. Kovač 2020).

The option that got the minimal support by respondents in the previous question—new towers in the BW Project—was somehow an overture in the last block of two questions. It concerned this project in progress, which is certainly the largest one along the entire riverfront in Belgrade. The first question was more related to the new promenade along the Sava River, in front of the new towers (Figure 2). The answers about the general affinity toward the promenade were rather divided by respondents (Figure 8, left), but the relative majority of respondents (42%) appreciated the new development. In the last question of the survey, which closely connected the promenade with the BW Project, to a large extent the attitude of respondents was a bit different (Figure 8, right). While the majorityFigure of respondents 8. The thematic did question not walk No. more 10 (left ofte) andn along No. 11the (right Sava) (author:River after B. Antoni´c2018). the completion of the promenade Figurein the front8. The of thematic the project, question a sizable No. 10 minority(left) and No.did 11(23%). (right ) (author: B. Antonić 2018). 4.2. Research B: Social Media 4.2. Research B: Social Media The second part of this research was focused on the analysis regarding information and communications technologies (ICTs) about urban space derived from social media. The ICT term in the context of this analysis should be understood as integrated telecommunication, software, and multimedia technology and systems, which ultimately allow users to manipulate the stored and transmitted data [46]. In this analysis, the data had to be related to the environment. Thus, geo-tagged data were selected as appropriate, due to their clear spatial visualization [47]. The synergy between technology and the built environment inﬂuences urban culture with digital streams. Furthermore, the future of urban space depends on the role of ICTs and the importance of their networks should be reconsidered since they have become indispensable ingredients of urban life [48]. ICT provides the overlapping of real and virtual spaces, thus allowing the creative participation of users. Figure 8. The thematic question No. 10 (left) and No. 11 (right) (author: B. Antonić 2018).

4.2. Research B: Social Media Sustainability 2020, 12, 6620 9 of 16

The research experiment was based on the Twitter Search Engine application developed for Twitter data gathering, mining, and classification. This type of methodology uses Twitter REST API as a protocol allowing data mining and different type of analysis and representation of User-Generated Content. Twitter Search Engine is a web application that enables the collection, storage, processing, and analysis of data from the social network Twitter. It is the micro-blogging platform that provides a rich collection of real-time commentaries on almost every aspect of life. Data collection is based on the Twitter REST API [49] that allows the collection of tweets in the space defined with geo-referenced points and the given radius. This API provides a wide range of information related to tweets and users who post them. In addition to basic information, such as text, time, or the number of retweets, the number of likes and information about the application from which it was posted/sent, as well as the geographical location where the tweet was shared, present the basis for the analysis and processing of geospatial data [50]. The application Twitter Search Engine (TSE) allows collection and storage of data for an unlimited period of time; it offers a display, analysis, and execution of complex geospatial queries of the data stored in the database. These queries are executed with the help of relational geospatial functions offered by the MySQL database. TSE functions are correlated in terms of interrelationship between two objects determined with geo-referenced points. Furthermore, TSE has the option of drawing a polygon on the map of Google by using Google Maps JavaScript API. This polygon site must be within the area for which information was collected. The research of Twitter data measured for the entire Sava riverfront in Old Belgrade, from the BW Project to the confluence of the Sava into the Danube near the “Milan Gale Muškatirović”Indoor Arena, was conducted. The geo-referenced tweets were collected from 2015 that concurred with the start of construction (July 2015) up to the period (August 2018) when the first two residential buildings were finished (Table1). In the meantime, in 2017, a new promenade along the Sava was inaugurated and opened for public. From 2015 to 2018, the number of tweets noticeably changed. The average number of tweets for the analyzed waterfront per month for 2015, 2016, and 2017 was 19.83, 13.25, and 14.00, respectively, or 14.83 as a month average for the period 2015–2017. On the other hand, during 2018, the number of tweets more than doubled—31.75 per month.

Table 1. The comparison of the number of tweets for the Sava waterfront within the analyzed period from July 2015 until August 2018 (authors: J. Jokovi´cand N. Dinki´c,2018).

Year Number of Tweets 2015 2016 2017 2018 January / 8 6 39 February / 19 17 25 March / 21 19 39 April / 15 14 35 May / 14 12 34 June / 9 11 23 July 12 15 14 28 August 13 10 10 31 September 25 8 17 / October 28 8 13 / November 14 19 14 / December 26 13 21 / Total 118 159 168 254 Average 19.83 13.25 14.00 31.75

The spatial distribution of the photos taken by Twitter in Old Belgrade in the analyzed period (2015–2018) indirectly represents the increase of the importance of the Sava waterfront. In 2015, the only place on the riverfront that was a major Twitter spot by photos taken was the aforementioned Beton Sustainability 2020, 12, x FOR PEER REVIEW 10 of 17 Sustainability 2020, 12, x FOR PEER REVIEW 10 of 17

October 28 8 13 / October 28 8 13 / November 14 19 14 / November 14 19 14 / December 26 13 21 / December 26 13 21 / Total 118 159 168 254 Total 118 159 168 254 Average 19.83 13.25 14.00 31.75 Average 19.83 13.25 14.00 31.75

SustainabilityThe spatial2020, 12 distribution, 6620 of the photos taken by Twitter in Old Belgrade in the analyzed period10 of 16 The spatial distribution of the photos taken by Twitter in Old Belgrade in the analyzed period (2015–2018) indirectly represents the increase of the importance of the Sava waterfront. In 2015, the (2015–2018) indirectly represents the increase of the importance of the Sava waterfront. In 2015, the only place on the riverfront that was a major Twitter spot by photos taken was the aforementioned onlyHala place as an on already the riverfront established that place was fora major socialization Twitter spot on the by riverfront photos taken (Figure was9, the left). aforementioned Nevertheless, Beton Hala as an already established place for socialization on the riverfront (Figure 9, left). Betontwo new Hala places as appearedan already in 2018;established the area place south for to Betonsocialization Hala (passenger on the pier)riverfront and the (Figure BW Project 9, left). site Nevertheless, two new places appeared in 2018; the area south to Beton Hala (passenger pier) and Nevertheless,(Figure9, right). two new places appeared in 2018; the area south to Beton Hala (passenger pier) and the BW Project site (Figure 9, right). the BW Project site (Figure 9, right).

Figure 9. Hotness of a spot indicating the number of photos taken in Belgrade 2015 ( left) and 2018 Figure 9. Hotness of a spot indicating the number of photos taken in Belgrade 2015 (left) and 2018 (right) (authors: J. Jokovi Jokovićandć and N. Dinki Dinkić,2016-18;ć, 2016-18; graphical arrangement: V. Kovaˇc2020).Kovač 2020). (right) (authors: J. Joković and N. Dinkić, 2016-18; graphical arrangement: V. Kovač 2020). In order to properly illustrate the possibilities of the TSE, tweets that were collected for the In order to properly illustrate the possibilities of the TSE, tweets that were collected for the Belgrade riverfrontriverfront overover a a period period of of eight eight months months (January–August (January–August 2018) 2018) were were spatially spatially analyzed analyzed and Belgrade riverfront over a period of eight months (January–August 2018) were spatially analyzed andthe resultsthe results of this of analysisthis analysis are shown are shown by the by space the space defined defined by the by corresponding the corresponding polygon polygon on the on map, the and the results of this analysis are shown by the space defined by the corresponding polygon on the map,together together with thewith spatial the spatial distribution distribution of tweets of tweets (Figure (Figure 10). 10). map, together with the spatial distribution of tweets (Figure 10).

Figure 10. Geospatial distribution of the tweets for the central part of the Belgrade riverfront for the Figure 10. Geospatial distribution distribution of of the the tweets tweets for for the ce centralntral part of the Belgrade riverfront for the period of January–August 2017 (authors: J. Joković and N. Dinkić 2018). period of January–August 2017 (authors: J. Jokovi Jokovi´candć and N. Dinki Dinki´c2018).ć 2018).

TSE also has the ability to detect the language using web service Language Detection API [51]. This API has the capacity to detect 160 different languages and to offer 5000 requests for free on a daily basis. Each request must contain a text and API key (The request example can be found at: http://ws.detectlanguage.com/0.2/detect?q=buenos+dias+se~nor&key=demo). Language Detection API produces results in the *.json format. The response contains an array of language candidates. Sustainability 2020, 12, x FOR PEER REVIEW 11 of 17 Sustainability 2020, 12, x FOR PEER REVIEW 11 of 17 TSE also has the ability to detect the language using web service Language Detection API [51]. This TSEAPI alsohas thehas capacitythe ability to todetect detect 160 the different language languages using web and service to offer Language 5000 requests Detection for freeAPI on[51]. a dailyThisSustainability APIbasis. has2020 Each the, 12 ,capacityrequest 6620 mustto detect contain 160 adifferent text and languages API key (Theand torequest offer 5000example requests can forbe foundfree11 on ofat: 16a http://ws.detectlanguage.com/0.2/detect?q=budaily basis. Each request must contain a textenos+dias+señor&key=demo). and API key (The request example can be Languagefound at: Detectionhttp://ws.detectlanguage.com/0.2/detect?q=bu API produces results in the *.json enos+dias+señor&key=demo).format. The response contains an array of Languagelanguage Each object contains a language code, confidence score, and if it is reliable—true/false. The cumulative candidates.Detection API Each produces object contains results ina languagethe *.json code, form coat.nfidence The response score, containsand if it isan reliable—true/false. array of language statistics for the considered period were as shown in Table2. Thecandidates. cumulative Each statistics object contains for the consider a languageed period code, wereconfidence as shown score, in Tableand if 2. it is reliable—true/false. The cumulative statistics for the considered period were as shown in Table 2. Table 2. Cumulative statistics of the tweets for the Sava waterfront collected in the period of Table 2. Cumulative statistics of the tweets for the Sava waterfront collected in the period of January–August 2018 (authors: J. Jokovićand N. Dinkić2018). January–AugustTable 2. Cumulative 2018 (authors:statistics J.of Jokovi the ćtweets and N. for Dinki theć Sava2018). waterfront collected in the period of January–August 2018 (authors: J. JokoviNumberć and ofTweets N. Dinkić 2018). 254 Number of Tweets 254 NumberNumber ofof of Users Tweets Users 111254 111 NumberNumberNumber of of Retweetsof Retweets Users 111 7 7 NumberNumber of of Favorites FavoritesRetweets 49 7 49 NumberNumberNumber of ofof Followers FollowersFavorites 339,010 339,010 49 NumberNumberNumber ofof of FriendsFollowers Friends 116,328339,010 116,328 NumberNumber of of Applications Applicationsof Friends 116,328 8 8 NumberNumber of of Applications Languages 17 8 Number of Languages 17 Number of Languages 17 The results of data classification are also given by the time intervals related to user activities per hour,TheThe weekday, results results andof of data data month classification classification (Figures 11 are are and also also 12). given given by by the the time time intervals intervals related related to to user user activities activities per per hour,hour, weekday, and month (Figures 11 and 1212).).

Figure 11. Temporal classifications of the tweets for the central part of the Belgrade riverfront per Figure 11. Temporal classifications of the tweets for the central part of the Belgrade riverfront per hour hourFigurefor January–August for 11. January–August Temporal 2018classifications 2018 (Authors: (Authors: J.of Jokovićandthe J. Jokovitweetsć for N.and Dinkić2018).the N. centralDinkić part2018). of the Belgrade riverfront per hour for January–August 2018 (Authors: J. Joković and N. Dinkić 2018).

FigureFigure 12. 12. TemporalTemporal classifications classifications of of Tweets Tweets for for the the ce centralntral part part of of Belgrade Belgrade riverfront riverfront per per month month (Figure(leftleft)) and and12. perTemporal per weekday weekday classifications (right (right) for) for January–Augustof January–AugustTweets for the 2017. ce 2017.ntral Left part Leftim age:of image:Belgrade Blue columns—tweets; Blue riverfront columns—tweets; per month Dark columns—images(Darkleft) and columns—images per weekday posted posted( righton Instagram) onfor InstagramJanuary–August via Twitter via Twitter (authors: 2017. (authors: Left J. Jokovi image: J. Jokovićandć andBlue N. columns—tweets; Dinki N.ć Dinkić2018). 2018). Dark columns—images posted on Instagram via Twitter (authors: J. Joković and N. Dinkić 2018). InIn addition addition to to the the spatial spatial and and temporal temporal distributi distributionon of of tweets, tweets, their their content content can can be be analyzed analyzed and and classifiedclassifiedIn addition by language to the usingspatialusing thethe and TSE TSE temporal application. application. distributi To To repeat, onrepeat, of Twittertweets, Twitter hastheir has the content the possibility possibility can be to analyzed share to share the dataandthe dataclassifiedthrough through di byfferent language different applications, using applications, the such TSE as application.such Instagram as Instagram orTo Foursquare. repeat, or TwitterFoursquare. All usedhas the applicationsAll possibility used applications by to Twitter share the areby dataincluded through in the different language applications, analysis (Figure such 13 as, left). Instagram The share or ofFoursquare. used languages All used on tweets applications collected by in the analyzed area was as shown in Figure 13, right. Sustainability 2020, 12, x FOR PEER REVIEW 12 of 17

Twitter are included in the language analysis (Figure 13, left). The share of used languages on tweets Sustainabilitycollected in2020 the, 12 analyzed, 6620 area was as shown in Figure 13, right. 12 of 16

Figure 13. Distributions of tweets by used applications and languages for the analyzed part of the BelgradeFigure 13. riverfront Distributions (authors: of tweets J. Jokovićand by used N.applications Dinkić,2018). and languages for the analyzed part of the Belgrade riverfront (authors: J. Joković and N. Dinkić, 2018). Interim conclusions regarding the tweets’ classification, language determination, and sentiment analysesInterim for the conclusions central part regarding of the Sava the tweets’ waterfront classifi in Belgradecation, language are: determination, and sentiment analyses for the central part of the Sava waterfront in Belgrade are: Spatial frequency: Most tweets were located in the Savamala District along the Sava, with Beton • • HalaSpatial as frequency: its northern Most tip tweets to the were confluence located in (Figure the Savamala 10). The District Danube along waterfront the Sava, inwith the Beton city centerHala as was its farnorthern less vibrant tip to the considering confluence the (Figur tweets.e 10). The The only Danube noticeable waterfro polent in was the around city center the “Milanwas far Gale less Muškatirović”Indoorvibrant considering the Arena, tweets. which The has only a high noticeable concentration pole was of diaroundfferent the sport “Milan and recreationGale Muškatirovi facilities.ć” Indoor Arena, which has a high concentration of different sport and Temporalrecreation frequency: facilities. This zone was vibrant during the weekend days—Saturday and (late) Friday • • (FigureTemporal 11), frequency: as well as inThis the eveningzone was time; vibrant tweets during were thethe mostweekend frequent days—Saturday at 9 p.m. and and generally (late) aboveFriday the (Figure average 11), until as well midnight. as in the evening time; tweets were the most frequent at 9 p.m. and Thegenerally zone is above becoming the av internationalerage until midnight. due to the high number of languages used in tweets (Figure 13, •• right).The zone However, is becoming it seems international that local usersdue to are the still high prevalent; number forof languages example, considering used in tweets the (Figure period of13, January–August right). However, 2017 it seems (Figure that 12), local the zone users has ar moree still tweets prevalent; during for spring example, months considering than during the summerperiod of ones, January–August which is generally 2017 the(Figure only 12), period the when zone therehas more are more tweets foreign during tourists spring than months local peoplethan during in central summer Belgrade. ones, which is generally the only period when there are more foreign Despitetourists thethan previous local people conclusion, in central the Belgrade. content of Figure 13 also reveals that international visitors •• (mainlyDespite tourists)the previous have becomeconclusion, the emergingthe content user of groupFigure of13 the also Belgrade reveals waterfrontthat international in recent visitors years. There(mainly were tourists) 12 languages have become used with the aemerging noticeable user share group (0.4%–2.0%), of the Belgrade but they waterfront were far behind in recent the twoyears. most There used were languages, 12 languages English used (global with/59.8%) a noticeable and Serbian share (domestic (0.4%–2.0%),/28.3%). but they were far behind the two most used languages, English (global/59.8%) and Serbian (domestic/28.3%). 5. Discussion 5. Discussion The results and interim conclusions derived from both research methods require the following in-depthThe examinationresults and interim and discussion. conclusions derived from both research methods require the following in-depthIn the examination case of the survey, and discussion. some correlations between question results, as well as between respondent groups,In arethe valuablecase of tothe comprehend survey, some the generalcorrelations respondent between opinion question on theresults, Belgrade as well waterfronts as between and theirrespondent current groups, development. are valuable They were to comprehend done by Chi-squared the general statistical respondent testing, opinion which on is usedthe Belgrade when a statisticallywaterfronts important and their di ffcurrenterence isdevelopment. anticipated between They were the expected done by frequencies. Chi-squared These statistical differences testing, can bewhich the indicatorsis used ofwhen new a and statistically/or unexpected important trends difference and tendencies. is anticipated The most importantbetween the observations expected infrequencies. this testing These are as follows:differences can be the indicators of new and/or unexpected trends and tendencies. The most important observations in this testing are as follows: The Danube waterfront is more used by the “younger” population (the groups of 16–24, 25–34, •• andThe 35–49Danube years), waterfront while the is more Sava waterfrontused by the and “you Adanger” Ciganlija population sport and(the recreationgroups of area16–24, are 25–34, used equallyand 35–49 among years), all agewhile groups. the Sava The waterfront comparison and between Ada Ciganlija the Danube sport and and the recreation Sava is expected area are becauseused equally the Danube among waterfront all age groups. is greener The andcomparison with more between sport andthe recreationDanube and areas the than Sava the is Savaexpected waterfront, because but the the Danube case of waterfront Ada Ciganlija, is greener which and resembles with more the sport Danube and waterfront recreation more,areas isthan unexpected. the Sava waterfront, but the case of Ada Ciganlija, which resembles the Danube waterfront Theremore, isis nounexpected. clear correlation between the certain age groups and the frequency of their use of the • waterfronts. In other words, the entire Belgrade waterfront is still functionally and physically open and accessible to all Belgradians. This indirectly confirms that many people visit the waterfront Sustainability 2020, 12, 6620 13 of 16

parts and areas that are the most accessible to their homes, i.e., there are no obstacles, for instance, heavily gentrified or gated ones, to opt for far-distant parts. Very interesting correlations can be extracted regarding the spatially related reasons for choosing • a certain part of the Belgrade waterfront, with the preference of the Danube/Sava waterfront. The respondents who opted for the Danube part preferred it due to the greenery and better pavement and paths, while those who preferred the Sava part, chose it for accessibility and leisure facilities, such as cafes and restaurants. A clear distinction between them is visible: the Danube is more for active free time (sports, walking), while the Sava is more for slow free time related to the hospitality sector. The other enlisted reasons are not decisive between the Danube and the Sava waterfronts. In the case of the questions connected to the Belgrade Waterfront Project, there are two tendencies. • The first one is that there is no specific difference regarding the satisfaction with the BWP and its Sava promenade between different age groups and between the respondent groups with a different frequency of use. The second tendency pertains to the observed dichotomies, such as between the groups relating to • the main reason for which they used the waterfront. Participants who mainly used the waterfront area for their recreation or leisure supported the BWP more than the participants who used it for the other reasons, mostly related to their daily routine, such as walking with children or with the dog. The second dichotomy is in the satisfaction with the BWP between the respondents who used the opposite sides of the Sava River. Those who used the opposite side in New Belgrade were obviously not satisfied with the new skyline of the BWP. However, the respondents who preferred the BWP promenade along the Sava were satisfied with its ambient properties and facilities. The last dichotomy refers to the spatially related reasons for the use of the Belgrade waterfronts. The respondents who particularly appreciated the new design and width of pavement, cafés, and restaurants were fond of the BWP, while the others who preferred sports facilities, greenery, and the quality of urban furniture were more against the project.

The discussion about the interim conclusions of the Twitter social media leads to similar findings. This analysis is more focused on the central part of the Old Belgrade waterfront. A general finding is that this area has been more interesting for social media users since the start of the BWP,which underpins that this project has had an impact on the use of this part of the waterfront. Similarly, the well-established Savamala District, next to the BWP area, with a vibrant, alternative, and progressive night scene was the most “tweeted” area for the period of 2015–2018. The transition zone between Savamala and the BWP areas actually had the highest concentration of tweets, which alludes to the rise of the attractiveness of the BWP. Expectedly, based on the previous findings, certain user groups are more visible. For example, tweets were more frequent during weekends as well as in the evenings, which indicate that this zone is becoming a place for going out and clubbing. This finding is further supported with the overall internationalization of this waterfront part, observable through the high preference of the use of English language in tweets. International visitors and tourists are known for their attachment to leisure facilities and the hospitality sector.

6. Conclusions Findings from the two presented analyses demonstrate that recent riverfront development projects along the Sava River in Old Belgrade have already made a rather strong impact on its users. They are becoming familiar with new city parts, regardless of their (positive or negative) stance toward them. The last two questions in the survey show that the relative majority of respondents like and use the new riverfront along the Sava River in Old Belgrade, which can be appraised as a success for this relatively short section of the city waterfront. Similarly, the analysis of tweets, as a major social media channel, indicates the rise of users and hot spots for taking photos in the same part of the waterfront. Sustainability 2020, 12, 6620 14 of 16

The survey also reveals that the Sava and the Danube are equally popular among the Belgrade population. However, considering the city center is situated in the Old Belgrade area, the Sava is far more popular than the Danube. Likewise, the Danube riverfront is not interesting enough for Twitter users. Knowing that the historic cores of the main Eastern European cities have witnessed a sharp increase of interest and in urban interventions during post-socialism, these facts demonstrate that the Sava riverfront in central Belgrade has been better exploited than the Danube, which certainly needs new incentives and projects. The results from the Analysis B indirectly suggest that the group of international users is becoming significant in the waterfront areas in central Belgrade. The results from language-based content indicate that this group is highly heterogeneous, which indirectly means that the Belgrade waterfront has made a positive impact on the diverse groups of international visitors. The previous findings clearly confirm that the potential of the Sava riverfront has been intensively developed and utilized in recent decades. Nevertheless, the focus from its transformation into a green and recreational zone during socialism has been redirected to the increase of its urbanity and centrality in post-socialism. The intensity of the use of the sport and recreation area around the “Milan Gale Muškatirović”Indoor Arena underpins that active leisure is still important for Belgrade dwellers, which can be promoted in both the improvement of already forming areas, such as the BWP area, and in completely new projects. To conclude, it is crucial to omit any tension between these two approaches in the future. This means that new projects along the Sava require a balance between open public spaces, indicated as important for recreation and leisure by the survey, and buildings and unavoidable elements for the economic development of contemporary cities. Skyscrapers as prospective landmarks can be an imperative for users’ orientation along and familiarization with the riverfront projects, but they are also sensitive segments that require detailed planning and design to fulfill the general expectations of all citizens.

Author Contributions: Conceptualization, B.A.; Data curation, V.K.; Formal analysis, J.M.; Investigation, J.M.; Methodology, A.D.; Resources, J.J. and N.D.; Software, J.J. and N.D.; Supervision, A.D.; Validation, J.J.; Visualization, B.A. and V.K.; Writing–original draft, A.D. and B.A.; Writing–review & editing, J.M. and V.K. All authors have read and agreed to the published version of the manuscript. Funding: This research received no external funding. Conﬂicts of Interest: The authors declare no conﬂict of interest.

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