Rawapening Lake Research Articles

Spatio-Temporal Analysis of Water Hyacinth Density (Eichhornia crassipes) in Lake Rawa Pening 2019 - 2023 Using NDVI Algorithm on Google Earth Engine (GEE)

Abstract Water hyacinth (Eichhornia crassipes) is an aquatic plant that floats in freshwater waters that has the ability to grow very fast and is invasive. This plant is able to reproduce vegetatively and generatively and is able to double its population within two weeks so that it can endanger the ecosystem in the waters. The purpose of this research is to map the distribution pattern, dynamics of changes in vegetation density and changes in water hyacinth area with spatial-temporal techniques using remote sensing technology processed using GEE in Lake Rawa Pening. The satellite image used is Sentinel level-2A with high spatial resolution with a recording time of May 2019 - 2023. This study uses the NDVI method to measure the greenness of vegetation and help identify the density of water hyacinth vegetation. The results of the vegetation density index show that there are five classification for vegetation density levels, and the outcomes of the accuracy test that was conducted range from -0.15 to 0.94. obtained an overall accuracy of 86.6% and a kappa coefficient value of 0.81. These results show that the use of Sentinel 2A imagery can be used for vegetation density index mapping using the NDVI algorithm in GEE with a good level of accuracy and conformity between map and field and the image processing that has been done is appropriate.

Evaluation of sediment transport estimates using Sediment Routing Analysis (SRA) model: study case of Rawa Pening Lake

Evaluation of sediment transport estimates using Sediment Routing Analysis (SRA) model: study case of Rawa Pening Lake

Spatial Distribution of Water Quality Classes of Rawa Pening Lake

Abstract Rawa Pening Lake is a source of water for irrigation and clean water for the people around the lake. The quality of water is the primary concern for sustainable functioning. This study aims to examine the water quality status of the lake under government regulations. The variables are temperature, total dissolved solid (TDS), total suspended solid (TSS), Escherichia coli (E. coli), dissolved oxygen (DO), biological oxygen demand (BOD), chemical oxygen demand, phosphate, nitrate, and oil. The study was conducted during the rainy season, from September to November 2020. It’s because of the season that farmers and the community use more of the lake water. The method used is purposive sampling, where a total of 12 locations represent each village, inlet, and outlet. The data analysis used is Storet to determine the water quality class and Inverse Distance Weighted (IDW) for the spatial distribution of water quality classes. The results showed that the water quality class of the lake suffered mild pollution. TSS and DO were variables that influenced that condition. It can be concluded that the lake has sucked sedimentation as a result of the deposits of mud and sand, which can damage the ecosystem of the lake.

Food Habits of Indigenous Fish Groups Caught in Lake Rawa Pening, Indonesia

Food Habits of Indigenous Fish Groups Caught in Lake Rawa Pening, Indonesia

Assessing payment for ecosystem services to improve lake water quality using the InVEST model

Payment for ecosystem services is a conservation strategy designed to offer farmers financial incentives for managing land to provide ecological benefits without disturbing livelihoods. However, the distribution of spatial financial feasibility is challenging when implementing this strategy on watershed scale. This study aimed to develop payment for ecosystem services model to improve quality in lake water catchment. The model estimated incentive values based on the costs of farmers’ losses, water yields, and pollution loads. The potential loss was calculated by determining the income of farmers in lake water catchment spent on land conversion from intensive agriculture to agroforestry. Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) modeling tool was used to calculate water yield and pollution load. The model was tested with case study approach at Lake Rawa Pening in Indonesia, consisting of nine sub-basins and 75 village administrations. The results showed that the reference compensation for farmers was 1,255.97 USD/ha/year. Considering the spatial distribution of water yields, the incentive for each village varied widely from 891.54 USD/ha/year to 1,557.06 USD/ha/year, even within the same sub-basin. Ten villages had an incentive above 1,450.00 USD/ha/year. However, considering the water pollution load, 26 villages had an incentive above 1,450.00 USD/ha/year with a maximum of 2,024.17 USD/ha/year. Therefore, village boundary should be an analysis unit for determining spatial incentive feasibility rather than a sub-basin boundary. Moreover, the level of water pollution load can become an additional variable to justify the amount of incentives received by farmers.

Comparison of SWAT-based Ecohydrological Modeling in the Rawa Pening Catchment Area, Indonesia

The Soil and Water Assessment Tool (SWAT) is an ecohydrological model widely applied to assess water quality and watershed management. This tool also has the advantage of building watershed models even with limited monitoring data availability. The essential data required by this tool includes digital elevation models (DEM), land use maps, climate data, and soil data. Nonetheless, the availability of spatial data is still often a challenge in developing hydrological models, especially in developing countries such as Indonesia. This research will compare the accuracy of freely available data in Indonesia in facilitating the development of hydrological models from SWAT in the Rawa Pening catchment area. This research is crucial since Rawa Pening Lake is a priority lake for revitalization, so the research results will help provide suggestions regarding presenting data in SWAT modeling. This research compares SWAT models built from different land use and DEM (Digital Elevation Models) data. The land use data being compared is the result of processing from the Google Earth Engine (GEE) platform using machine learning with land use data from government agencies, namely the Ministry of Environment and Forestry, while the DEM data being compared is SRTM and DEMNAS data. The validation results using R, R2, RMSE, and NSE show that, in general, the model built from land use from GEE is the best compared to the other models. In modeling SWAT in Indonesia, we recommend using good-quality land-use data. Utilizing supervised classification through Random Forest (RF) algorithms within GEE can facilitate the acquisition of this data. To reduce computation time, the DEM can be SRTM with a small sacrifice of accuracy.

Physico-Chemical and Biological Water Quality of Tuntang Estuary, Demak, Central Java as A Base for Sustainable River Management

The estuary, downstream of the river, accumulates pollutants from upstream and marine. Tuntang is one of the major rivers in Central Java, 139 km length from Rawapening Lake, and ends in the Java Sea. Mangroves are the dominant riparian vegetation in the downstream and estuary of the Tuntang River. This research analyzes the water quality and pollution index (PI) of Tuntang Estuary, Demak. Water samples were collected from four sites in February (wet season) and September 2022 (dry season) and were analyzed for temperature, TDS, pH, BOD, COD, DO, nitrate, nitrite, ammonia, TN, TP, Cd, Cu, Pb, Cr, fecal coliform, and total coliform. The water quality parameters of Tuntang Estuary in the dry season exceeded the threshold for Class I-III, such as TDS in T1 ((2530 mgL-1), BOD (4.06-5.12 mgL-1), COD (28.32-102 mgL-1), DO for Class I and II (3.93-4.28 mgL-1), Pb at T1 and T3 in the wet season, and T1 in the dry season, and Cr for Class I, II, and III (. 0.05 mgL-1), Pb (T1), and Cr for Class I, II, and III (. 0.05 mgL-1). In contrast, in the wet season, BOD (4.37-7.15 mgL-1), Pb (T1 and T3), fecal coli, and coliform exceeded the threshold. The TN (0.83-2.48 mgL-1) and TP in the wet season (0.45-0.53 mgL-1 at T1 and T1) indicated that Tuntang Estuary was in the eutrophic condition. Based on the PI method, the water quality of Tuntang Estuary is good to slightly polluted for Class I, II, and III. The sustainable river management that is appropriate to be developed for the Tuntang River is conserving the mangrove ecosystem in the Tuntang Estuary.

Analysis of The Effect of Different Types of Bait on The Catch of Freshwater Lobster (Cherax Quadricarinatus) on Umbrella Trap in Rawa Pening Lake, Semarang Regency, Indonesia

Analysis of The Effect of Different Types of Bait on The Catch of Freshwater Lobster (Cherax Quadricarinatus) on Umbrella Trap in Rawa Pening Lake, Semarang Regency, Indonesia

Vertical Distribution of Diatoms Analysis to Determine the Condition of Rawapening Lake in the Past through Cluster Analysis with the Bray-Curtis Model

Vertical Distribution of Diatoms Analysis to Determine the Condition of Rawapening Lake in the Past through Cluster Analysis with the Bray-Curtis Model

Specifications and net construction of tilapia nets in Rawa Pening Lake

Specifications and net construction of tilapia nets in Rawa Pening Lake

Lake and Stream Buffer Zone Widths' Effects on Nutrient Export to Lake Rawapening, Central Java, Indonesia: A Simple Simulation Study

Lake ecosystems in Indonesia face serious environmental problems. One of those problems is eutrophication caused by excessive plant nutrients, particularly nitrogen (N) and phosphorus (P). Water quality degradation and biodiversity loss are the effects of eutrophication. The government of Indonesia (GoI) has issued a regulation on determining lake and stream buffer zones, but it has not been fully implemented in the field. Additionally, the data related to the effects of each buffer zone width is not available. This study aims to begin to fill this gap. It simulates the effect of lake and stream buffer zone widths on nutrient export to Rawapening Lake. The Nutrient Retention sub-model, which is part of InVEST (Integrated Valuation of Environmental Services and Tradeoffs) software, has been used for this research to analyse information from several data sources, including a Digital Elevation Model (DEM) and measurements of soil depth, annual rainfall, land cover/use, watershed/sub-watershed boundaries, and biophysical conditions. Several studies of eutrophication in Rawapening Lake have measured the magnitude of eutrophication but have not discussed the effects of buffer zone widths. Therefore, this study accommodates the updated data on how much effect of buffer zone widths on the reduction of nutrient export. Five scenarios of buffer zone width are considered: 30 m., 90 m., and 150 m, where the lake buffer zone widths and the stream buffer zone width are 30 m. The results indicated that the maximum nutrient export reduction of lake buffer zones was only 2.63% (for N) and 3.56% (for P). On the other hand, the 30 m stream buffer zone width reduced the nutrient export to Rawapening Lake by up to 43.05% for N and by 44.90% for P. A 30 m combined lake and stream buffer zone width slightly increases the nutrient export reduction effectiveness, i.e., 0.41% and 0.56% for N and P, respectively.

Community Empowerment Through Making Iboni Craft to Improve Community Welfare and The Economic Impact

The people of Rowoboni Village have not optimized the potential of water hyacinths in Lake Rawapening. People only work as laborers picking water hyacinths and selling raw to collectors. It does not improve the community’s economy because the selling price of water hyacinths is still lower than that of water hyacinths processed into handicraft products. This study aims to describe the process of water hyacinth Iboni craft community empowerment to improve community welfare and economy. This qualitative approach used in-depth interview techniques with 14 participants consisting of one manager, seven workers, four devices village, one farmer, and one hyacinth collector who are considered to have precise information related to the focus of the research. Data collection techniques in this study used observation, interviews, and documentation. Data validity applied source triangulation techniques, and the data were analyzed through data collection, reduction, presentation, and conclusions. The results of this study show that the empowerment process of Iboni craft consists of 3 stages, namely 1) awareness and behavior formation, 2) knowledge and skills transformation, and 3) intellectual and skills enrichment or improvement. The economic impact of this empowerment program is increasing people’s income and welfare. The conclusion is that the empowerment process of Iboni Craft consists of 3 stages: 1) awareness and behavior formation through Dialogical communication or word of mouth to the public, 2) knowledge and skills transformation through group training, and independent training with the manager of Iboni Craft, 3) intellectual and skills enrichment or improvement where the workforce begins to produce independently following consumer demand. The economic impact of this empowerment program is an increase in family income, which can provide the family with a second source of income.

FEASIBILITY AND SUITABILITY ANALYSIS OF CANDIREJO AND LOPAIT VILLAGES TO BECOME AGROTOURISM VILLAGES

Tuntang District is located in Semarang Regency, Central Java Province. This district has an aquatic landscape, namely Rawa Pening Lake. Rawa Pening Lake has attractive natural tourism potential because of its very beautiful natural scenery and Rawa Pening Lake is sorrounded by mountains. In addition, the lake area is also used as a place for fish cultivation because the outskirts have fish cages, and are also used for irrigation of rice fields. However, this potential has not been developed properly. So the purpose of this research is to analyze the suitability and feasibility of Candirejo Village and Lopait Village to become agro-tourism villages. The research method used is to identify land use using a classification method based on the condition of satellite imagery, Analyzing the social conditions (perceptions) of the community, where the sample was selected using the stratified random sampling method, Analyzing the visual conditions (landscape aesthetics) using the Scenic Beauty Estimation (SBE) method, and Assessing the feasibility and suitability of each village based on the results of the previous three stages. The results of the study can be seen in the table of the total value of all the variables in the 2 agro-tourism villages. In conclusion, Candirejo Village and Lopait Village have the potential to be used as agro-tourism villages, but Lopait Village still needs to be improved in several variables.

Revitalization of Rawa Pening lake, Indonesia

Rawa Pening Lake has been in critical condition, caused by high sedimentation levels, declining water quality, damage to the watershed, and excessive riparian occupation. Therefore, this study aims to identify the main problems of the revitalization of Rawa Pening lake. Data and information collection were carried out through direct observation and interviews. The results showed that the main problems of the lake were the removal of the water weeds/water hyacinths, tidal rice fields, and buildings on the lake and riparian areas. The solution to the three main problems is lake revitalization. The revitalization concept that can be proposed regarding the control of water hyacinth is by mechanical means (using water hyacinth lifting equipment, boats, and cutting water hyacinth) and by biological methods, namely the cultivation of koan fish that will eat water hyacinth. At the tidal rice fields, it is necessary to determine the water level limit wisely. The areas with elevation of 462.30 m3-463.25 m3 (covering an area of 812 Ha) can be planted twice a year. The areas with a height of 462.05 m3-462.30 m3 (covering an area of 200 Ha) can be planted once in the rainy season. The areas with elevation of 462.05 m3 cannot be planted because it is in a state of flooding. Incommensurate areas and lakes, there is a lot of land and buildings consisting of settlements, tourism destinations, places of worship, and restaurants. Then the proposed alternative solution is the land acquisition compensation of land and buildings in commensurate areas.

Analysis of Rawa Pening Lake Morphometric Changes for Identification of Land Arises

Rawa Pening Lake is a natural lake with the status of a critical lake in Indonesia because there is an uncontrolled population of water hyacinths, so a layer of water hyacinths covers the surface of the water. Sedimentation causes indications of the appearance of soil to arise. Based on this, it is essential to monitor the presence of surface soil. This study aimed to determine changes in the morphometry and morphology of Rawa Pening Lake, to study changes in morphology, and the spatial distribution of land arising indicative of Rawa Pening Lake. The study This data used the satellite imagery of Landsat 5 in 1989, Landsat 7 in 2002, and Landsat 8 in 2015 and 2021. The method used is NDWI (Normalized Difference Water Index) and manual interpretation to distinguish between water and non-water areas. The results showed that the use of the NDWI method was not optimal for determining the firm boundaries of the lake. The manual interpretation method shows that in 1989–2002, Rawa Pening Lake experienced a narrowing with a change in the area of 75,639 Ha and the distribution of indicative raised land of 141,146 Ha. From 2002–2015, the lake experienced an increase in the area of 159,734 Ha, and the total area of indicative arising land distribution was 99,285 Ha, and in 2015–2021 there was a change in the area of 230,192 Ha with the distribution of raised land of 18.010 Ha.

RISK FACTORS TO TOURISM VISIT DECISIONS WITH DESTINATION IMAGE AS A MEDIATION: CASE STUDY OF RAWA PENING LAKE, INDONESIA

The purpose of this study was to determine the risk factors that influence the decision to visit with the image of the destination as a mediating variable. A quantitative method for data processing using SPSS and AMOS - SEM software as instruments. The survey was conducted on 229 respondents who had visited Rawa Pening lake tourism, Central Java, Indonesia. The results obtained confirmed that the perception of cognitive risk and financial risk contributed greatly to the visit decision, either directly or through the mediation of cognitive attraction and effective image. While socio-psychological risk is less impactful even though it is through cognitive attraction and directly, the role of the affective image can bridge visitors to visit. The two mediators helped the community decide to visit this tourist area.

A Holistic Review of Lake Rawapening Management Practices, Indonesia: Pillar-Based and Object-Based Management

Lake Rawapening, Semarang Regency, Indonesia, has incorporated a holistic plan in its management practices. However, despite successful target achievements, some limitations remain, and a review of its management plan is needed. This paper identifies and analyzes existing lake management strategies as a standard specifically in Lake Rawapening by exploring various literature, both legal frameworks and scholarly articles indexed in the Scopus database and Google Scholar about lake management in many countries. By using Publish or Perish with the keywords “lake management” OR “management of lake”, 1532 and 1990 works from the Scopus database and Google Scholar, respectively, have been reduced 37. The results show that there are two major types of lake management, namely pillar-based and object-based. The holistic review has resulted in nine points of pillar-based management, which consists of conceptual paradigms as the foundation, and 11 points of object-based management to restore or preserve the lake, which is in line with the form of programs and activities. Overall, Lake Rawapening management should be concerned with finance and technology when applying pillar-based management, and it should include more activities within programs on erosion-sedimentation control as well as monitoring of operational performance using information systems to ensure the implementation of activities within programs in applying object-based lake management.

Policy Content Analysis of Rawapening Lake Management Team

Rawapening lake is one of multifunction lake in central java province. It is one of the priority lake in Indonesia. Rawapening Lake has been degraded due to its function. The most visible impacts are the decreasing of physical and chemical quality of the lake water and the decreasing of the lake carrying capacity. There have been several policies of Lake management in Indonesia, but most of lakes condition in Indonesia are still degrading. The Governor Decision number 610 was issue in 2019. This policy is about establishment of Rawapening Lake management team form multi stakes holder which consist of steering team, implementing team which consist of five working groups. Since the establishment of Rawapening lake management team, reportedly there has been positive changes in Rawapening condition. The content of this policy can be the key to sustainable lake management in Indonesia. The content analysis of the Rawapening management team is subjected in to three focuses as follows: the duties of steering team, the duties of implementing team, what have the working group done as part of the implementing team.

Rawapening Lake Buffer Zone Management

Abstract. Rawapening Lake is located in Semarang District, Central Java. The decreasing of Rawapening lake function due to its many problems caused by environmental degradation which has happened for almost three decades. Buffer zone determination is a very important basic action to safe Rawapening Lake. This research is to determine Rawapening lake buffer zone and its management. Hydraulic, topographic analysis was conducted within the research along with identification of buffer zone condition. A clear buffer zone area act as boundary for Rawapening lake utilization to support the sustainability of its function in the future.

Characterization of Three Selected Macrophytes – An Ecological Engineering Approach for Effective Rehabilitation of Rawapening Lake

Characterization of Three Selected Macrophytes – An Ecological Engineering Approach for Effective Rehabilitation of Rawapening Lake