Design of Retention Pond Kacang Pedang Area as a Water Tourism Recreation Using Water Sensitive Urban Design

The issue of changes in natural conditions, Pangkal Pinang City as a downstream area of the Baturusa Watershed (DAS) with a city center whose city morphology is a basin resulting in Pangkal Pinang City receiving excessive water runoff, plus land deforestation due to illegal mining in the upstream river which is directly adjacent to the Regency Central Bangka which causes excessive sedimentation and poorly connected drainage channels. The existence of high rainfall intensity and the uncontrolled capacity of the retention pond causes the water level to rise which then flows into the retention pond area. As a result, the Rangkui river causes excessive water runoff, resulting in floods that spread to residential areas and the center of Pangkal Pinang City. The purpose of this study was to provide design concepts for the retention pond area using the Water Sensitive Urban Design method as a strategy for urban water management, particularly in the region of raw water sources. The design process is a fragmented one that starts with a collection of regional design-related problems and ends with a simulation of regional design. Recreational, residential, and educational activities will all be accommodated within the design area’s 94 hectares. The design of the area will focus on urban design elements combined with normative principles, namely land use, intensity and building, circulation and parking, pedestrian ways, open spaces, signage, preservation, and activity support. In addition, the design simulation will also focus on the water management system in the area with a WSUD technical approach that is directed to focus on efforts to infiltrate rainwater and provide rainwater storage containers, both in open spaces, green areas, and buildings.


Introduction
According to Moretti [1], "waterfront" refers to an urban region that is near water.According to the author, port infrastructure and port activities typically occupy shoreline areas.According to [2], the waterfront is commonly understood to be the region where urban growth meets the water.According to Hou (2009), the waterfront is where water and land meet.The idea of waterfront spaces is also frequently used in cities to raise the standard of the metropolis.The construction of waterfront spaces represents an effort to transform an underutilized space into a community with a range of activities.The river border area and underneath the retention basin are two places in Pangkal Pinang City that receive less attention when it comes to quality of life.Due to its geographical location downstream from the Batu Deer Watershed (DAS) and its city centre's basin shape, Pangkal Pinang City receives surface runoff from the upstream area as well as land degradation from illegal mining in the upstream river, which is next to Bangka Regency.When rainfall intensity is high and the capacity under the retention basin is improperly controlled, a rise in water level results, which then flows into the area under the retention and the Rangkui river, causing water runoff.Central, which results in excessive sedimentation and poorly connected drainage channels.Flooding caused by excessive rain causes residential neighbourhoods and Pangkal Pinang City's center to flood.In its current condition, the area under retention is mostly designated as trade and service activities located on the border under retention which is a waterfront tourism area and culinary tourism.There is vacant land that has not been developed optimally as well as areas that have moderate slum settlements and the number of irregular street vendors which causes the impression of slums in the area under the retention.The development of the area under the Peanut retention area is certainly inseparable from the efforts of the Pangkal Pinang City government to redevelop the retention pond area by developing the area under the retention area into a water tourism recreation area while still focusing on the ecological aspects of the environment under the retention.There are problems and potentials that can be developed into a water tourism recreation area.Furthermore, under retention area can also be developed into an urban green area that focuses on ecological aspects in overcoming environmental degradation and minimizing the impact of urban flooding, which then becomes the background for the research and design with the title of designing the area under the Kacang Pedang retention as a tourist recreation space.water with a Water Sensitive Urban Design concept approach.The use of the concept of Water Sensitive Urban Design will refer to problems related to water management to control floods, water pollution and green open spaces.

Methodology
The fragmental rational design method was employed in the creation of this study [3].The fragmental approach uses parts of the synoptic method's design process, or a combination of the synoptic and intuitive methods, but does not use the complete synoptic method's design process.Because the steps taken do not need to be consecutive and are very brief, the fragmental method was chosen.

Waterfront
A waterfront is defined as a location that borders and deals with seas, rivers, lakes, and other bodies of water [4] The physical contact between the region and the sea at its edge along the waterfront serves as a guide for the growth of its physical development.Environmental awareness, clean water, pressure, the growth of the downtown area, and urban redevelopment all have an impact on whether there is a waterfront development element.The improvement of the waterfront city area is often highly beneficial to raising the physical appeal of the city and boosting its economy.According to [5], there are three different sorts of waterfronts, as follows: 1. Conservation is the arrangement of ancient or old waterfronts that still exist and keep them for the benefit of the community.2. Redevelopment is an effort to revive the old waterfront functions which are still used for the benefit of the community by changing or rebuilding existing facilities.3. Development is an effort to create a waterfront that meets the current and future needs of the city.
Based on its function [5], waterfronts can be divided into 4 types, namely: 1) Mixed-used waterfront is a waterfront which is a combination of housing, offices, restaurants, markets, hospitals, and/or cultural places.2) Recreational waterfront are all waterfront areas that provide facilities and infrastructure for recreational activities, such as parks, playgrounds, fishing grounds, and facilities for cruise ships.3) Residential waterfront is housing, apartments, and resorts built on the waterfront.4) Working waterfront, are places for commercial fishing, repair of cruise ships, heavy industry, and other functions [5] State that a few factors are taken into consideration when deciding whether an area qualifies as a waterfront or not.whether or not to go to the waterfront.The ensuing standards are established: 1) Situated on or on the edge of a body of water, such as a river.Usually, it is a port, a commercial, a residential, or a tourist area.2) Is primarily used as a recreation area, community, industrial hub, or port.
3) Be in control of the natural surroundings and the direction that leads to the water.4) Both a vertical and a horizontal axis are used in the construction.

Retention Ponds and Dry Ponds
Ponds According to [7] reservoirs or retention ponds are temporary reservoirs for channel discharge so that during peak floods it can be reduced or reduced.Meanwhile [8] this construction aims to regulate the discharge flowing downstream according to the cross-sectional capacity so that the flow can be flowed when the flood recedes.The function of the retention pond is as a catchment area which is used as a closed area with the function of infiltration being replaced by a retention pond.The function of this pool is to collect direct rainwater and flow from the system to be absorbed into the ground.The retention pond is placed in the lowest part of the land that is converted into a residential area.Another function of the retention pond is as flood control and water distribution, waste treatment, retention ponds are built to facilitate the maintenance and purification of reservoir water, because it is much more efficient in purifying the water in a small retention pond before it flows into the reservoir than draining or purifying the reservoir water.[9] Retention ponds have a sufficiently high capacity to remove most of the pollutant load from settlements.Retention ponds can be designed to have a single function, namely for the purpose of improving runoff quality, or they can also be designed to have multiple functions, namely, to prevent flooding.Retention ponds can work well if there is a flow in and out of the pond.If planned and maintained properly, retention ponds can be developed into recreational areas, green open spaces, backup water sources for firefighters, and other aspects [10].

Flood
The most frequent source of flooding, according to [11] and [12] is when the water level in the river rises to the point where the river extends beyond its shores ('fluvial').The terms flood and flood cover a very wide variety of phenomena, and each requires a different type of management.Floods are considered a "invisible risk" because they frequently happen suddenly and in places that are not obviously prone to flooding.According to their point of origin and geographic location, the two major types of flooding are discussed in  Integrated Flood Management (IFM) is an approach developed from the concept of Integrated Water Resources Management (IWRM).IWRM is a process that aims to synergize the management and development of water resources, land, and other related resources to maximize economic and social benefits fairly without compromising the sustainability aspects of utilization and ecosystems [14].The aspects of integrated flood management are as follows: 1. Traditional flood management is more focused on structural control and protection efforts, so integrated flood management is a proactive flood risk management concept, with a holistic approach.2. Integrated flood management emphasizes the link between flood management and socio-economic development and ecosystem protection.
3. Integrated flood management integrates all planning, implementation (construction), and operational/maintenance efforts that must be taken before, during and after a flood event, including efforts to formulate and implement policies in terms of water management, land management, and risk management aspects.4. In the realm of IWRM, there are several steps for implementing water resources management as follows: 1. Initiation of government commitments, visions, and policies.2. Situation and problem analysis.
3. Selection of strategies, priorities, and goals.4. Planning and approval of policy makers.5. Implementation, starting from legal, institutional, action management, and capacity building aspects.6. Evaluation of progress and revision of plans; and back to the first point.

Water Sensitive Urban Design
Water Sensitive Urban Design (WSUD) is one part of the concept of a green infrastructure approach.The purpose of this conceptual approach is to approach urban planning and design related to water resources and environmental management and to minimize the impact caused by the presence of water on the urban surface [15] Initially, this concept emerged against the background of the role of water in urban life, which requires a harmonious arrangement between urban development and the need for water.The concept of Water Sensitive Urban Design focuses on the sustainable management of the water cycle in the city where this management is the source of this conceptual approach [16].The forms of water cycle sustainability management are drinking water management, water flow caused by rain, water quality, wastewater management and water cycle (water conservation) [17] The benefits of implementing the development of an area, including: 1. Improve water conservation 2. Improving stormwater quality increases Biodiversity and the concept of Water Sensitive Urban Design in 3. Habitat diversity 4. Reducing greenhouse gas emissions by reducing water consumption and increasing rainwater harvesting 5. Support local food production 6.Reducing flood risk 7. Realizing the concept of green infrastructure 8. Creating attractive places

Urban Design Principle
Based on the literature review and precedent studies that have been carried out regarding the waterfront area under retention with the concept of Water Sensitive Urban Design, then the formulation of city design principles is carried out which is then used as a reference for designing the waterfront area under retention with the WSUD concept approach.From the results of the formulation of the principle, then it is explained based on two criteria for the principle of city design, namely place and people, in which there are 8 principles of city design in considering the development of waterfront areas under retention by applying the WSUD concept.Then the basis of these principles will then be implemented into the design criteria of each component of the principal elements of urban design that will be developed in the design of the area footprint.As for a clearer explanation, it can be seen in the following

Diverse
Space that is diverse and presents a variety of experiences.

Enduring
Space that is sustainable and enduring, as well as adaptive.

Design principles of People
Comfortable A comfortable space that can invite people.

Vibrant
An active space and community interaction that supports Safety A space that provides a sense of security and protection

Walkable
Creating a comfortable space for walking and minimizing motorized vehicles

Retention Pond Capacity
The retention pond was made with the aim of being a catchment area for rainwater at the design area site.The retention pond is directed to maximize runoff capacity at the site and is added to the capacity of the wetland at the site.The dimensions of the retention pond are determined based on the average elevation with a height of 4 meters to 7 meters based on data (google earth) and study results (Reliability study under retention), [18] as well as the area under retention.The description of the altitude data is as follows:  From the explanation above, an analysis of the carrying capacity volume at the site of the design area shows that the area under the retention of sword nuts can accommodate runoff water.This is based on the elevation at the normal water level and the upper water level in the area under the Peanut Sword retention and the area under the retention area which is then calculated by calculating the volume of water carrying capacity at the site.As for more clearly can be seen in the following table and figure:

Vibrant
As one of the developments with the concept of waterfront areas under retention are: recreational waterfront, Public Open Space -Amphitheater, Playground, Sport center, Picnic Area & Campground, Fishing Pier, Waterplay Area, Viewing deck, Shelter.

Intensity and Massing Building Diverse
The mass of the building carries the concept of environmentally friendly buildings Safe The river border line follows the rules of 50-100-meters from the underside Connected Areas with regional and tourism-scale trade and service functions have a KDB of 80% Enduring The use of rainwater management techniques using the concept of WSUD elements that are suitable to be applied to the site area.Enhancing • General Provisions Zoning of KLB protected areas with a maximum of 0.5 KDH and a minimum of 90%

Conclusion
The design of the waterfront area or waterfront with the concept of water tourism recreation under retention in this thesis uses a water sensitive urban design concept approach.It can be concluded that the area under the Peanut Sword retention area has the potential to be developed into a water tourism recreation area based on the environment and can also become one of the new tourism areas of Pangkalpinang City.In addition to the potential in the area, the problem around the lack of green open space and the effectiveness of the under-retention capacity that has not been maximized, environmental degradation is something that must be considered so that we can find a good approach to minimize these problems.The water sensitive urban design technique approach in area design can be implemented to maximize rainwater infiltration and provide water catchment areas and rainwater containers, to minimize excessive rainwater runoff on residential and urban surfaces.This is because the area under the Peanut Sword retention is one of the main water catchment areas of Pangkalpinang City to reduce the threat of flooding and the rising water level under the retention area which results in residential areas and urban centers.In addition, the concept of rainwater infiltration is also expected to improve the condition of groundwater quality in the area to minimize the impact of land subsidence.The existence of rainwater reservoirs can also be used by the community and residents of the area to meet their needs for clean water without having to take groundwater.The design of the area in general illustrates that the WSUD technique can be implemented at the site of the area to maximize water absorption and densely populated areas by maximizing water catchment and absorbing into the ground.

Figure 3 .
Figure 3. Urban Water Management (A.Hoban and T.H.F.Wong.2006 [6]) [13]. 1. Inland flooding, primarily caused by rain (fluvial).2. Watershed flooding brought on by a rise in river levels because of rain or snowmelt (fluvial).3. Flooding at sea caused by a combination of tides.

Figure 5 .
Figure 5. Elevation Diagram of the Design Area (Google Earth Pro, 2022) The calculation of the carrying capacity under the retention using the digital elevation model (DEMNAS) data which has been interpolated with the data, then the raster data is animated in 3D form the area under the retention and surface volume is performed on the software.ArcGIS 10.8.The schematic depiction in calculating the area and volume is as follows:

Figure 6 .
Figure 6.Illustration of a cross-sectional calculation of the volume area on the top and bottom surfaces (desktop.arcgis.com)

table . Tabel 1 .
The concept of urban design principle