On the rapid process of urbanization in developing countries it is not surprising that many spots in urban areas could be found informal settlements particularly squatters on riverbank in most Indonesian cities, such as Jakarta, Surabaya, Palembang, Semarang, Yogyakarta, etc. The informal settlement is any residential activities in any areas that are conducted without formality aspect relating to the government, such as tax, regulation, location permit, license, etc.This paper will analyze the landscape of the informal settlement on the Code Riverbank in Yogyakarta to respond the urban heat island issue. Landscape is characterized by a broad area of common unique visual character based on physically land-form, vegetation, water-form, and land-use pattern. Urban landscapes with a high content of vegetation elements in particular, have thus potentials to perform a variety of social functions and as such to establish or regain a role of healthy, desirable and restorative urban landscapes. However, on the Code Riverbank in the city of Yogyakarta, there are many informal settlements that dominate the land-use pattern of the urban riverfront. The physical component of the high density of the informal housing represents a variety of social functions of urban land-uses. The high density of the informal settlement on the Code riverfront has avoided the ecological function of the Code watershed. The high density of the informal housing is able to influence the urban temperature in Yogyakarta that support the issue of urban heat island issue as a part of global warming phenomena. “Urban Heat Island” (UHI) refers to the tendency for a city to remain warmer than its surroundings. The analysis of the UHI issue will focus on the natural aspect of environment; particularly vegetation that is crucial component of the cooler urban landscape, including urban riverfront. The research suggest that the informal housing density in urban riverfront has visually represented a low content of natural landscape, particularly land-form, vegetation and water and this visual has reduced the uniqueness of the natural potential of the Code Riverfront. This phenomenon has a contribution to the higher level of urban temperature as an aspect of the UHI effect. Another finding is that a balance development between natural and man made component on the river watershed of the Code Riverfront will support a cooler urban landscape.
Key Words: Urban landscape, informal settlement, Urban heat Island, Code Riverfront, Environment.
Landscape study has been practiced in the earliest time, when human pointed out where is the best location for agricultural field, trade center, or even built houses. Historically, it was found that city or other growth points located near water sources and surfaces, such as beach or river. During that time, river was threat as a main water source and play as a natural drainage system on continuous water cycle. By the time of population growth, urbanization, and invented technology in all sectors including constructions, increases the needs of more houses, paved streets, and other built area. Resulting in lessen vegetation in the way to occupy all land that human can found, including riverbanks that referred to be watershed and do not permitted to built.
Development caused by human created serious changes that affect river landscape. Code river, one of three main rivers in Yogyakarta are being degraded with loosing its function as main water source and remarked with squatter occupies its riverbanks with informal settlements, formed a slum area.
Informal Settlement on the Code Riverfront : Site Conditions
Chode River is one of three main rivers lying in Yogyakarta Province that consisted of Chode River, Gajahwong River, and Winongo River. Based upon regional administration, Code river stated in three municipalities, Sleman, Bantul, and Jogja city. The upper stream were drawn from north side, Merapi Mountain until its lower downstream in the south, meeting in a cross section with Opak river in Bantul municipality. Following natural cycle of water and topographic land slopes, river have special characteristic so that what happen in upper stream would have affecting the downstream area. According to these passage, the upper stream area of Chode river should threatened as a water reservoir area with preservation and needed conservation that means development and built area were restricted.
Figure 1. Code River in the City of Yogyakarta
But the fact is not the same as an ideal concept. The upper stream area of Code River were slowly developed with squatter settlement, ignoring its natural function as water reservoir. In urban area, Code riverside conditions become more complex with high density settlement that tends to be slum area. Based on statistical research in 2005, from 151,420 households that lived in Jogja city, 2.14% of them lived next to riverside including in Code riverside called Code community. Code community were formed of 71% native people and 29% migrants. Most of them (53%) has been living there for more than 25 year.
The term of informal could be determined as anything conducted without formality or ceremony (Wester, 1999). Using this as analogy, informal settlements then referred as settlements without any supported formality aspects relating to the government. Informal settlement were often remarked with its illegal status of land owning. Reported on this definition, most of dwellings settled on Code riverbanks were marked as an illegal or informal settlements. From data survey collected with direct observation, it was founded that less than 50% of settlements have a legal documents supported. Only 38% of settlements in Code riverbank already have SHM (Certificate of Land Property) and 9% only have HGB (Right of Using the Property). Most of them (40%) have to pay for living in those area by rent a land or property. And the rest of them (11%) still lived in “Magersari. In term of rights for build property, 61% of them don’t have IMB (Rights to Build Property) that means, 61% of building settlements on Code riverbanks are illegal. Hence, the survey reported that 47% of people lived in Code riverbanks get their land as an inheritance land.
Based on its conceptual categorization, informal settlements were classified into three types, (1) Unauthorized land development or informal subdivision, (2) squatter settlements, and (3) informal rental housing (Durand-Lasserve and Royston, 2002 in Royston and Narsoo, 2006). Those concept reflected most of informal settlements concept that marked it as visual pollution and social economic problem. The other concepts of informal settlements rely on the paradigms that informal settlements is a kind of solution for poor and marginal urban people. Informal settlements could be viewed as great intelligence in the use of resources, in shifting single use to mixed use, from low density to high density, and from absence of infrastructure to full infrastructure (Srilestari, 2005).
RT 69/RW 19 Dusun Karang Anyar Kelurahan Bronto Kusuman was recorded density value for 481 people/hectares, made it classified as high density area. Within these area, more than 60% of settlements were too small to be noted as dwellings. Most of settlements in Code riverside have a mixed-use, commonly for economic function. Visually, the main characteristics of informal settlements in Code riverside were high density, small size houses, lack of ventilation, and narrow streets. This conditions brought a high health risk, such as tuberculosis endemic (Chrysantina, et.al, 2004).
Reviewing Code’s community economic life, 47% of them work as labor while 38% work as an entrepreneur, and the rest of them work as official government, farmer, and working in informal sector. Economic survey of Code community determining their income resulted in 39% of them received Rp. 300.000-Rp 500.000 per month, 32% received Rp 100.000-Rp. 300.000 per month, 13% received less than Rp 100.000 per month and the others received more than Rp. 500.000 per month.
The expansion of Code riverside by squatters was determined by two reasons, the first one was the independent status of land, encouraging people to squatter. While the second reason for Code riverside expansion was represented cultural, economic, and social demands (Solihah, 2004). Through survey and direct observation, it was founded that the reason in choosing Code riverbanks as their settlements were compiled and classified into three main reasons, as an economic motivation (33%), for comfort living (40%), and as a forced movement option because they didn’t have another choice for living place (27%).
Figure 2. Code informal settlements, high density, small size houses and lack of ventilation
With high density and high population indeed, waste become a problem. For Code community, littering it away to the river was an easy and cheap way. By some recent years, it became a more serious problem causing degradation of river quality and higher risk of flood. In 2003, 53 illegal depo was recorded to be found in Code riverside (Bakti Setiawan, PSLH, 2003). From the other Code’s study, it was founded that an area with high density would raised the risk for groundwater pollution too (Yorhanita, 2001). It was reported in Harian Jogja, 26 December 2007 that Code is the most polluted river among three main rivers in Yogyakarta Province.
Natural conditions of river landscape providing a proper drainage system and well-continuous water cycle. When rainfall occurs, it was absorbed by vegetation that covering the soil surface (half for itself and half as groundwater) and the others gently returned to surface water such as river or lake. By the river stream, the water journey continued to the sea, which a great evaporation took place, formed a clouds, and thus became a rainfall again.
Figure 3. Natural Water Cycle
Source : Site Planning; Storm-water Management by North Carolina Department of Environment and Natural Resources Division of Water Quality, 1998
By the change of human development, the contours are smoothed and the landscape is comprised of hardened surfaces (rooftops, paved streets, etc.). These changes resulting in higher run off velocity that increased erosive potential. Hence, at a high concentration of rainfall, it can be resulting as floods or landslide.
Figure 4. Natural drainage system and areas to be protected
Managing river landscape then became an important material to protect riverside settlements from floods and landslide. It comes with zoning system through watershed, determined whether an area is safe for built area or not. Minimum space between river and built area were required to ensuring safety zone. Those zoning system were drawn on Figure 1.
According to government riverside policy that laid down by Indonesian Ministry of Civil Works in 1993, minimum space required between Code river and built area is 15 meters, but considering existing situation that has been crowded and high density, the official government of Jogja city determined 3 meters space between river and built area. The ideal solution to fix this problem is relocating Code community to someplace safe with higher quality of living and environment, but both social and economic cost of relocation process tends to be too expensive.
Figure 6. No spaces between settlements and Code river
The Urban Heat Islands Effect
Urban heat Island is a phenomenon where urban areas become warmer than suburbs, its surrounding areas. It was first observed in London and other European cities in 1830s (Yamamoto, 2007). In that time, urban heat islands were considered as positive impact on reducing heating equipments during the winter. As machinery and automobile grew, created great reliance on air conditioning system, the negative effects of urban heat island appeared with the increasing temperature on summer, made it less comfortable for human (Meier).
Figure 7. Urban Heat Island Profile
Source: Lawrence Berkeley National Laboratory in Solecki,et.al, 2004
Urbanization that followed by rapid development that make less vegetation in order to be replaced by concrete materials was determined as significant factors that causing urban heat island. Its cycle were described in this flow chart on Figure 8.
Figure 9. Significant Factors causing Urban Heat Island Effects
Source : Japan Minstry of the Environment, 2000
In order to examine urban heat islands in informal settlement on Code riverfront, several important factors were drawn, including (1) buildings, (2) road system, (3) vegetation and greenbelt system, and (4) water system. Those factors affect directly through the wind paths. Wind paths then affecting urban heat islands phenomenon by decreasing temperature through mixing warm air with fresh air that come from suburbs.
Characteristics of Code riverside settlements with high density building, small size houses, and lack of ventilation keep heat temperature trapped inside buildings, make it less comfortable for dwellings.
According to urban heat islands phenomenon, dense and tall buildings could created an urban basin that affect wind flows. Settlements in Chode riverside were consisted of one or two-story building that settled on land with different contours, next to the river, the lower it come.
(2) Road system
Road system on informal settlement on Chode riverfront was built in organic pattern, along with its organic settlement. The paved roads were narrow, with length about 2-3 meters, where cars didn’t allowed to pass. The road just fix for motorcycle, cycle, or walking, the three optional ways of local Chode community to mobile. Those narrow paved streets created a corridor that affecting urban heat effects by trapping heat temperature inside, make it warmer for human.
(3) Vegetation and greenbelt system
A study to generate urban heat island in Tokyo discovered that green parks has a significant effect on reducing temperature which is around 2 degrees lower than surrounding built areas (Mikami and Kubo). Vegetation and greenbelt system conditions on Chode riverfront were vary in one to another area. In the north and south area of the riverside, vegetation and greenbelt system could be found, but less vegetated in the middle area. Those conditions make a middle area become the most warmer area than the other area along Chode Riverside.
(4) Water system
It s discovered that water system has a great effect in decreasing temperature, it’s almost twice stronger than greenbelt effect. With the greenbelt system, the value of decreasing temperature is nearly up to 50C (Du, et al, 2008). Water system took form as river could created wind path, blowing winds from sea to land or from mountain to valleys. In more specific ways, wind path along the river could (1) ) bring in cool air from the sea, lowering daytime urban temperatures, (2) bring in cool air currents that flow down mountain slopes and valleys, cooling hot urban air at night, and (3) help alleviate air pollution by bringing in generally cleaner sea winds and cool air currents (Science Council of Japan 2005 on Yamamoto, 2007).
Incorporated wind path along the river with building orientation could created greater effect on reducing urban heat islands temperature. When buildings are positioned parallel to a river, they interfere with the air flowing along the river, preventing it from finding its way into urban districts. Positioning buildings perpendicular to the river, effectively channels air flow into these districts. When buildings are positioned at a 45-degree angle to the river, however, they produce two contrasting effects, depending on the direction of wind flow along the river (Yamamoto, 2007).
Revitalization of Code River
Responding with urban heat islands effects, there are needs to change the landscape of informal settlements on Chode riverbanks through revitalization of Chode river. Changing the landscape must be consider with minimum space required between river and built area that ensuring safety zone for human activities. More vegetation needs to be planted to reduce urban heat island effects and as safety border for the settlements. If the changes of informal settlements landscape work properly, it would improve air quality and in long term could improve the quality of living of Chode community. Several ways for changing landscape on informal settlements on Chode riverbanks has been identified as follows :
- Plant more vegetation and created greenbelt system based on the concept of landscape sustainability that use native plants. The environmental design principles of landscape sustainability is (1) enhance landscape microclimate through channeling winds, shading structure, and humidity adjustment, (2)increase biodiversity, (3) reduce resource inputs and resource waste, and (4) maximize reuse of resources (Rodie, 2009).
More vegetation could reduce urban heat temperature, while greenbelt system could prevent settlements next to Chode river from landslide.
- Land readjustment. From the preliminary study, it was found that if the existing high density area of informal settlements were readjusted with 4 multi-stories building, there will be more than 50% open spaces available. The changing landscape of informal settlements on Chode riverbanks through land readjustment would gained built coefficient in 50% rates compare with open spaces including green belt and parks. The process of land readjustment should be under collaboration between government, local community, and academicians, so that multi-stories building could have a legal acknowledgement.
- Created community based tourism for Chode river. There are some tremendous tourism attractions, such as natural river view in the north area of Code river, small and home industries supported, cultural festival “Merti Code”, held once per year, and cultural tourism. By developing community based tourism in Code riverfront, would encouraged Code community to improve their environment, keep it clean and comfortable to stay.
Natural river view in the north area of Chode river, potential to be tourism attractions
Merti Code festival (left) and home industries supported (right) as potential tourism attractions for Chode Riverfront Tourism
Community based tourism for Code river has been prepared (now still in progress) by Forum Pemerti Chode, consisted of Code community, local government, and academicians.
Based on river natural landscape, informal settlements on Chode river were built with ignoring minimum space required between river and built area, created high risk area with potential damage of flood and landslide. The main characteristics of informal settlements on Chode riverbanks were a high density dwellings, small size houses with most of them are mixed-use, lack of ventilation, and organic narrow paved streets created urban heat islands effects. Generally, quality of live on Chode informal settlements were decreased along with degradation of Chode river itself.
Changing landscape of settlements on Chode riverbanks by plant more vegetation with 50% rates compared with built area could reducing urban heat effects and improve air quality. Land readjustment process could improve river landscape and gained a legal status of settlements for local community. The other way to revitalize Code riverbank is by crated community based tourism that encouraging local community to keep their environment clean, healthy, and comfortable to stay.
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 Yogyakarta Province have a special policy referred to its special status that acknowledge Sultan’s land. People that lived in Sultan’s Land called “magersari”. They don’t have any payment for live or settled there, form as Sultan’s pity for his people in ancient time. The status of “magersari” are still debated by local government and national government.
 Minimum standard of revenue in Yogyakarta Province is about Rp. 700.000
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