Total Annual Value Research Articles

Development of a distributed hydrological model combined with sediment transport calculations and its application to a medium-scale basin in northeast China

Abstract An accurate assessment of sediment transport can assist land and resource managers in any region. The primary objective of this study was to develop a distributed hydrological model for calculating rainfall-runoff coupled with sediment transport to provide a practical method for estimating sediment transport in western Heilongjiang Province, China. The Alun River Basin, which has typical meteorological and hydrological characteristics of western Heilongjiang Province, was chosen as the study area. A sediment transport calculation module was developed based on physically based formulas for the suspended load and bedload, which was coupled with a numerical model of the physical distributed rainfall-runoff process. The model’s ability was validated by comparing the sediment sampling survey results of the particle size group distribution (PSGD) in the flow and the corresponding value of the model calculation results for a control case. The root mean square error (RMSE) and the mean absolute error (MAE) were mostly <10%. The model was used to calculate the rainfall-runoff combined with sediment transport in 2016, and the results indicate that the primary form of sediment transport was as suspended load. The suspended load accounted for over 90% of the total sediment transport caused by the maximum flood peak, and the suspended load accounted for over 80% during the period of normal water level across the selected sections. The sediment transport process was dominated by the runoff process. The contribution of the monthly sediment transport in winter to the annual total value was mostly <1%; while in the rainy season, the contribution of the monthly sediment transport to the annual total value was >15%. The results provide a basis for the assessment of sediment transport and the development of a numerical platform for modeling hydrological processes coupled with land surface processes in western Heilongjiang Province, China.

Value of lost leisure among sandwich generation women performing caregiving duties for older parents

This study evaluates the extent of leisure time loss experienced by middle-aged women in South Korea who care for their aging parents and quantifies the monetary value of this lost leisure time. By employing an open-ended direct question, we derived respondents' willingness to pay and willingness to accept compensation for leisure time lost due to caregiving duties. Our findings reveal that middle-aged women engaged in regular caregiving are willing to pay an average of 9313 KRW (US$7.74) per hour for leisure time and would require 13,539 KRW (US$11.40) per hour as compensation for their lost leisure. The annual total monetary value of leisure time loss for consistent caregivers was estimated to range between 7403.4 billion KRW (US$6232 million) and 10,127.5 billion KRW (US$8525 million). The study highlights the significant challenges faced by caregivers, particularly middle-aged women, emphasizing the need for social awareness and discussions on gender role distribution to promote gender equality. It underscores the importance of developing effective support policies, including financial compensation and mental health resources, to alleviate caregivers' dual burden of work and home responsibilities. Understanding the economic impact of leisure time loss can help address long-term socioeconomic issues associated with an aging society, crucial for improving the efficiency and sustainability of care services for the older generation. The economic value estimated in this study will provide essential information for evaluating the cost-effectiveness of public services, supporting the economic feasibility of policies and programs, especially because respite services involve significant government expenditure.

Integrative cultivation pattern, distribution, yield and potential benefit of rubber based agroforestry system in China

Rubber trees are the most widely cultivated natural rubber crops globally. Although commercial cultivation of rubber trees occurs in Hainan, Yunnan and Guangdong provinces in the tropical regions of southern China, adapting rubber plantations to global sustainable development remains a challenge. Particularly within rubber plantations, sustainability and efficiency in production and managements often suffer due to soil degradation resulting from monoculture land use and poor management practices. Rubber based agroforestry systems offer a sustainable approach to mimic natural ecosystem. This study aims to explore the patterns, distribution, yields and potential benefits of rubber agroforestry system. The results show that there were 15 types of rubber agroforestry patterns, including Rubber–Banana, Rubber–Pineapple, Rubber–Cassava, Rubber–Passionfruit, Rubber–Flower plants, Rubber–Ficus hirta, Rubber–Corn, Rubber–Edible fungus, Rubber–Alpinia oxyphylla, Rubber–coffee, Rubber–Phrynium hainanense, Rubber–Amomum villosum, Rubber–Amorphophallus, Rubber–Tea, Rubber–Pandanus amaryllifolius. These patterns are distributed across 17 counties in Hainan Province and 10 counties in Yunnan Province. The total area of rubber based agroforestry exceeds 79,520 ha, comprising 35,998 ha of young rubber agroforestry systems and 43,522 ha of mature ones. The total annual output value benefit of rubber agroforestry systems surpasses 834 million US dollars. Young agroforestry systems yield an annual output value of 269 million US dollars, while mature agroforestry systems contribute 110 billion US dollars from dry rubber and 455 million US dollars from integrative crops. Yunnan Province's economic output value for rubber agroforestry systems exceeds that of Hainan Province due to higher output values of passionfruit from young rubber plantations and Amorphophallus from mature ones. These results indicate the widespread acceptance of rubber agroforestry systems in China's rubber planting practices and their significant potential for output benefits. As environmentally friendly and sustainable production patterns, rubber agroforestry systems have the potential to enhance the sustainable livelihood capacity of smallholders and contribute to poverty alleviation efforts in China and globally. These findings enrich agroforestry systems science and provide valuable insights for optimizing industrial policies and technology transfer.

Optimization of Work Systems and Ergonomics to Improve Comfort and Efficiency Through The Implementation of Energy Management

This research aims to implement mall operations that are comfortable, efficient, and effective in energy use and determine the value of Energy Consumption Intensity (IKE). This research uses a qualitative method with a literature study approach. Research data was obtained from measurements carried out by researchers at mall buildings in South Jakarta. Instrument data is obtained from the installed Kwh meter. Data analysis technique by comparing measurement results with data results standardized by the Ministry of Energy and Mineral Resources for IKE and Indonesian National Standards for thermal comfort levels. The research results obtained show that the IKE value is classified as efficient. The IKE value during 2023 ranges from 8,79 – 11,37 kWh/m2/month with the total annual IKE value being 263,16 kWh/m2/year. In terms of air conditioning, the average comfort standard in 2023 will be 25℃ and RH (humidity) at 62.9%.

Capturing the net ecosystem CO2 exchange dynamics of tidal wetlands with high spatiotemporal resolution by integrating process-based and machine learning estimations

Accurate estimation of the net ecosystem CO2 exchange (NEE) at regional scales is of great significance for studying the carbon sink potential of coastal wetland ecosystems and their responses to global climate change. However, current NEE estimation methods are mainly developed for terrestrial ecosystems and are therefore unsuitable for NEE estimation with high spatiotemporal resolution estimation in coastal wetlands subjected to sub-daily tidal flooding. In this study, we proposed a high spatiotemporal resolution NEE estimation method for coastal marsh wetlands that properly considered tidal influence by combining the advantages of process-based modeling and machine learning. This method was verified and applied in the Changjiang estuary and Liaohe estuary marsh wetlands based on eddy covariance and environmental measurements, climate reanalysis data, and satellite images. The proposed method had good performance in the NEE estimation of tidal marsh wetlands, with Phragmites australis, Spartina alterniflora, and Suaeda salsa having coefficients of determination (R2) of 0.850, 0.676, and 0.658, respectively, and root mean square error (RMSE) values of 7.211 μmol m−2 s−1, 8.105 μmol m−2 s−1, and 0.109 μmol m−2 s−1, respectively. By integrating the tide level and salinity, the NEE estimation accuracy for each vegetation type was improved. The total annual NEE values of the Changjiang estuary and Liaohe estuary marsh wetlands in 2022 were estimated to be −0.297 and −0.444 Tg C yr−1, respectively. This study demonstrated that integrating process-based model and machine learning estimation can reliably capture the NEE dynamics of coastal wetlands, providing a useful tool to quantify coastal blue carbon potential with high spatiotemporal resolution at large scales.

Source analysis and health risk assessment of polycyclic aromatic hydrocarbon (PAHs) in total suspended particulate matter (TSP) from Bengbu, China

The polycyclic aromatic hydrocarbon (PAH) concentrations in total suspended particulate matter (TSP) samples collected from October, 2021 to September, 2022 were analyzed to clarify the pollution characteristics and sources of 16 PAHs in the atmospheric TSP in Bengbu City. The ρ(PAHs) concentrations ranged from 1.71 to 43.85 ng/m3 and higher concentrations were detected in winter, followed by spring, autumn, and summer. The positive matrix factorization analysis revealed that, in spring and summer, PAH pollution was caused mainly by industrial emissions, gasoline and diesel fuel combustion, whereas in autumn and winter, it was coal, biomass and natural gas combustion. The cluster and potential source factor analyses showed that long-range transport was a significant factor. During spring, autumn, and winter, the northern and northwestern regions had a significant impact, whereas the coastal area south of Bengbu had the greatest influence in summer. The health risk assessment revealed that the annual total carcinogenic equivalent concentration values for PAHs varied from 0.0159 to 7.437 ng/m3, which was classified as moderate. Furthermore, the annual incremental lifetime cancer risk values ranged from 1.431 × 10−4 to 3.671 × 10−3 for adults and from 6.823 × 10−5 to 1.749 × 10−3 for children, which were higher than the standard.

Assessing vegetation cover and valuing ecosystem services in southwestern Ethiopia: Implications for conservation.

The Bench-Sheko zone, parts of the Eastern Afromontane Biodiversity Hotspot, is characterized by its rich biodiversity. However, recent reductions in vegetation cover have drawn concern, highlighting the critical role of remote sensing in monitoring these alterations is critical. Furthermore, this study evaluates the economic value of the ecosystem services rendered by the diverse types of vegetation cover class in the area. The classification of vegetation types and measuring their ecosystem benefits are crucial for monitoring vegetation and analyzing land cover changes. estimating the value of ecosystem services is vital for environmental impact assessments, cost-benefit analyses, and creating payment schemes for these natural services. For the vegetation cover map, it uses Sentinel-2 satellite data and a Random Forest classifier using Google Earth Engine. Based on a properly chosen reference, ecosystem service assessment approaches include benefit transfer, direct market value, and the social cost of carbon. The results highlight the vegetation classes' enormous value and the services they offer. The largest value for Supporting Services (2829.3 USD ha⁻1yr⁻1) is found in the Remnant Forest, which makes up 30.98% of the total area. With the highest value for both cultural services (2847.7 USD ha⁻1yr⁻1) and regulatory services (5063.9 USD ha⁻1yr⁻1), the wetlands, which make up 4.35% of the total area, stand out. The total annual value of all ecosystem services provided by all vegetation classes is estimated to be 2.089 billion USD. When paired with methods for tracking and assessing changes in vegetation cover over time, high-resolution satellite images and precise classification algorithms can offer insightful information on the condition of the environment and support informed decision-making. In order to evaluate and convey to society and policymakers the advantages of vegetation cover, the value of ecosystem services is essential.

Measurement of radium and radon gas in bottled mineral waters.

In this study, the radon gas and radium concentration in the bottled mineral water samples was measured. A total of sixty samples were collected from bottled mineral water sold in the markets in Kahramanmaraş. DURRIDGE Rad7 electronic radon detector was used for measurements. Radon and radium activity amounts range from 33.50 ± 1.30mBq/L to 51.70 ± 2.20mBq/L, and 2.92 ± 0.15mBq/L to 4.51 ± 0.26mBq/L, respectively. Average radon and radium active amounts are 41.67 ± 1.54mBq/L and 3.63 ± 0.18mBq/L, respectively. Total annual effective dose values were calculated for these mineral waters according to three different scenarios. In the first of these, it was assumed that natural mineral water was consumed annually instead of 730 L of drinking water (S1). In the second case, 150 L which was the annual average amount of natural mineral water consumed in European Union member countries was used for the annual average amount of natural mineral water consumed by adults (S2). Finally, the annual average amount of natural mineral water consumed in Turkey, 14 L, was used for adults (S3). For scenarios (S1, S2, S3), the total (ingestion + inhalation) annual average dose values ranged from 6.83E-04mSv/y to 1.05E-03mSv/y, 1.40E-04mSv/y to 2.17E-04, and 1.32E-05mSv/y to 2.03E-05mSv/y, their average values were 8.49E-04mSv/y, 1.75E-04mSv/y, and 1.64E-05mSv/y, respectively. The total effective dose values calculated within the scope of the current study were below the limit value announced by WHO.

Medical expenditure trajectory and HbA1c progression prior to and after clinical diagnosis of type 2 diabetes in a commercially insured population in the USA

IntroductionMedical expenditures of individuals with type 2 diabetes escalate before clinical diagnosis. How increases in medical expenditures are related to glucose levels remains unclear. We examined changes in HbA1c and...

Measurements of natural radionuclide levels and hazards in the Lega Dembi gold mine, Oromia, Ethiopia

ABSTRACT This study aimed to evaluate natural radioactivity levels and hazards of radionuclides 232Th, 226Ra and 40K in soil samples taken from 15 locations in the Lega Dembi gold mining, Oromia, Ethiopia, using gamma-ray spectroscopy coupled with an HPGe detector. It was observed that the respective mean specific activities for 226Ra, 232Th and 40K determined in the mining site were 23.87 ± 0.7, 52.5 ± 1.8 and 391.62 ± 11.35 Bq/kg, and 8.89 ± 0.4, 13.83 ± 0.6 and 423.68 ± 9.5 Bq/kg in the living areas. The specific activity of 232Th was above the permissive limit in the mining site, while for 226Ra and 40K were within the limit. The specific activity of 40K in the living area was observed to be above the permissive limit. The calculated value of radiation hazards parameters; radium equivalent activity (Raeq), internal and external hazards indices (Hin) and (Hex), the mean annual effective dose (AED), and gamma representative indices (Iγ) were within permissively limit. The mean absorbed dose rate in the mining site was above the recommended safety limit. The total annual gonadal dose equivalent value was found to be 494.8 ± 8.7 µSv/a in the mining site. This value was also above the permissively.

The Influence of pH Dynamics on Modeled Ammonia Emission Patterns of a Naturally Ventilated Dairy Cattle Building

Ammonia emission rates from naturally ventilated livestock housing systems can be estimated in multiple ways. By coupling different modeling approaches towards a semi-mechanistic barn-scale ammonia emission model, we investigated the influence of urine puddle pH dynamics on the (sub)daily and seasonal pattern of ammonia emissions. We compared the simulated ammonia emission patterns using about ten months of on-farm measurements obtained from a naturally ventilated dairy cattle building with a scraped solid floor in Northern Germany. The dataset included gas concentration measurements as well as wind data (ranging from 0 m s−1 to about 8.6 m s−1) and air temperature data (ranging from about −4 ∘C to about 32 ∘C), the average number of housed cows (about 380) and information on the average cow mass (about 700 kg). In addition, the average dry matter intake, total gross energy intake and nitrogen intake were used to model the ammonia emission potential. In the emission modeling, we considered two potential types of pH dynamics in the urine puddles: a saturating scenario and a peaking scenario. For both of them, 21 different combinations of initial pH and maximum pH were considered within a range of 6.5 to 11. We showed that the non-linear interaction of the puddle pH and temperature caused specific emission patterns, where the degree of influence of the two parameters changed over the course of the emission process. Low initial pH values together with high asymptotic pH values were associated with the largest emissions. Considering the same asymptotic pH value, the higher the initial pH value, the lower the observed emissions; especially when assuming peak pH dynamics, the emission values were significantly lower. In natural pH settings (i.e., low to intermediate initial pH and intermediate asymptotic pH), the winter emissions were considerably lower than the summer emissions (i.e., the winter emission was about half of the summer emission, as observed in the on-farm studies). In contrast, artificial pH settings with high pH values led to markedly lower emissions in the summer (i.e., the summer emission was about the same as winter emission), reducing the total annual emission value. Our sensitivity study indicated that the urine puddle alkalizing dynamics play a key role in the overall emission model accuracy in order to capture seasonal and diurnal variability of the ammonia emission of naturally ventilated dairy cattle barns in mechanistic modeling approaches. Thus, future studies should investigate the range of pH dynamics that naturally occur in urine puddles in cattle barns depending on the flooring material, the entry of litter or feed leftovers, the cleaning and cooling system (e.g., in terms of use of water) and so on in order to further refine the emission model.

Comprehensive technical study of a novel polygeneration arrangement using natural gas power plant and geothermal energy for producing electricity, heat, fresh water, and methanol

Structural modifications play a crucial role in enhancing the sustainability of natural gas power plants owing to their significant contribution to greenhouse gas emissions and irreversibility factors. One primary solution is using waste heat recovery systems integrated with these power plants, producing different products. Furthermore, integrating renewable energy resources into the entire system within a co-feed framework may be a viable method for further enhancements. The current study focuses on a novel heat integration process combined with a natural gas power plant, which uses geothermal energy as an auxiliary energy source. The newly designed system encompasses a gas turbine cycle, two modified geothermal power plants, a water electrolyzer unit, and a methanol synthesis unit. The process is simulated utilizing the Aspen HYSYS software, and to evaluate its viability, analyses are performed pertaining to energy, exergy, environment, and economics. Furthermore, a comprehensive parametric analysis is conducted on the primary performance indicators. The simulation results show that the process’s energy, exergy, and electrical efficiencies equal 53.85%, 47.30%, and 40.26%, respectively. The environmental evaluation demonstrates that the specific carbon dioxide emissions associated with the total energy produced and the sum of power and heating are 0.27 kg/kWh and 0.294 kg/kWh, respectively. From the economic aspect, the total unit cost of the products and the cost of energy of the system are 20.69 $/GJ and 0.086 $/kWh, respectively. Also, total annual cost, investment cost, and net present value of 222.81 M$, 1010.64 M$, and 1220.57 M$, respectively.

Estimating the recreational value of mountain tourism to shape sustainable development in Gilgit-Baltistan, Pakistan

Mountain tourism has been experiencing remarkable growth in Pakistan, and the economy of mountainous regions is increasingly reliant on the tourism sector. However, the vulnerability of mountain tourism to climate change and human activities poses severe threats to its long-term sustainability, and addressing these challenges necessitates meticulous planning and immediate policy attention to effectively mitigate potential risks and secure the future of mountain tourism. This study aims to aid in formulating policies that promote sustainable mountain tourism by estimating the recreational value associated with high mountain tourism in Hunza Valley. The total recreational value is considered an indicator of the economic viability of tourism in high mountain regions. Data were collected from 1046 tourists through on-site surveys conducted during 2021–2022, and the estimation model employed a truncated negative binomial regression technique. This study reveals that the annual recreational value per person for visiting the Hunza Valley amounts to USD 126.3, resulting in a total annual recreational value of USD 22.8 million of the region. These estimations provide valuable insights to policymakers, enabling them to understand the area's economic potential better and facilitate efficient resource allocation strategies within the mountainous landscape. Furthermore, these findings offer critical guidance for informed decision-making concerning natural resource management, ensuring the conservation and preservation of the region's unique landscapes and historical sites.

Seasonal Monitoring of Water Quality Parameters and Pesticides at the Altınapa Reservoir Watershed

Altınapa Reservoir is a reservoir located on the Meram Stream in the Konya Province in Türkiye that supplies drinking water. The Altınapa Reservoir feeds the Konya Drinking Water Treatment Plant with 37.8 million m3 of water annually and the treated water is delivered by the drinking water network. The aim of this study was to determine the effect of agricultural activities and settlements on water quality in the Altınapa Reservoir Watershed. In the study, major water quality parameters (pH, electrical conductivity, total organic carbon, total nitrogen, nitrite, nitrate, phosphorus, phosphate, and total suspended solids) and pesticides were monitored at four stations (K1, K2, K3, K4) on the sub-streams feeding reservoir. Major water quality parameters were monitored at monthly intervals for 12 months between June 2020 and May 2021, and pesticides were monitored seasonally at 4 seasons (Fall 2019, Winter 2020, Summer 2020, and Spring 2021). A correlation matrix was used to assess the connections between nine indicators of water quality. The annual average conductivity and pH values of the samples taken from four different stations of the Meram Stream were 432 µS/cm and 8.04, respectively. The highest value for total nitrogen was 10.73 mg/L and it was 0.87 mg/L for nitrate. Annual average total organic carbon values were determined as 1.35, 1.69, 1.51, and 1.46 mg/L at K1, K2, K3, and K4 stations, respectively. Specific UV absorbance indicated that organic matters of water are mostly hydrophilic and have low aromatic content. In seasonal pesticide monitoring, 71 different compounds were detected in water samples. The compounds whose concentrations exceeded Turkish Environmental Quality Standards were identified as DDD-op, DDE-p.p', diflufenican, and imidacloprid. Pesticides constitute most of the micropollutants detected in water samples. The highest positive correlation among water quality parameters was obtained between conductivity and nitrate (0.81) and total nitrogen (0.88).

A “reserve” of regulating services: The importance of a remnant protected forest for human well-being in the Po delta (Italy)

During the last century the landscape of the Po delta (Italy), one of the most important European deltaic areas, was strongly altered by extended land reclamation and land use intensification. Consequently, the loss of the lowland forested area that was once extended along the region's coast took place. The present study aims to evaluate the ecosystem services provided by the Bosco Mesola woodland, a remnant-forested area of 1,058 ha located on an agriculture-dominated landscape, nowadays protected as a National Nature Reserve. Five ecosystem services were selected and evaluated both in biophysical and monetary terms, including provisioning (firewood production for industrial bioenergy and households’ heating purposes), regulating (air quality and climate regulation by carbon storage), and cultural services (eco-tourism), using experimental and collected data and modeling. The results underlined that the Reserve provides services for a total 10.4 M€ yr-1 and stores carbon for an estimated value of 7.2 M€. Notably, regulating services, such as air quality regulation (i.e. PM10 and O3 removal) accounts for 98.5% of the total annual value. While raising the issue related to the identification and conservation of ESs with no direct market value, whose socio-political and applicative fields have great relevance, this study demonstrates that remnant forests are exceptional providers of ecosystem services that can significantly contribute to reaching multiple sustainable development goals and whose preservation is largely remarked in EU Biodiversity Strategy for 2030. In this regard, the integration of different methods and data sources for ES assessment allow to capture a comprehensive range of ESs that may properly support the decision process.

Characterization of consumption and costs of antimicrobials in intensive care units in a Brazilian tertiary hospital

BackgroundThe consumption of antimicrobials and the growing resistance of infectious agents to these drugs are not related only to health issues, but also to economic parameters. ObjectivesThe study objective was to evaluate the consumption of antimicrobials in General and Covid-19 Intensive Care Units (ICUs) and the impact on institutional costs in the largest institute of a tertiary public hospital. MethodsThis is a quantitative and retrospective study, which analyzed consumption, through the Defined Daily Dose (DDD), and the annual direct cost of antimicrobials in Reais (R$) and Dollars (US$), from January to December 2021. ResultsThe total annual consumption (DDD/1000 patient-day) of antimicrobials in the ICUs was 14,368.85. β-Lactams had the highest total annual value, with a DDD/1000 patient-day of 7062.98, being meropenem the antimicrobial that reached the highest consumption (3107.20), followed by vancomycin (2322.6). Total consumption was higher in Covid-19 ICUs than in General ICUs, and the annual direct cost of antimicrobials in ICUs was US$560,680.79. ConclusionsThe study showed high consumption of broad-spectrum antimicrobials, highlighting the importance of structuring programs to manage the use of antimicrobials, both to reduce antimicrobial consumption and hospital costs, consolidating rational use even in pandemic scenarios.

Bioeconomics of Florida Recreational Fisheries to Estimate Willingness to Pay for Bag and Size Limits of Spotted Seatrout

This research focuses on the economic component of a bioeconomic model for spotted seatrout in the recreational fisheries on Florida’s west coast. A survey was designed to assess how anglers, who caught or targeted spotted seatrout on Florida’s west coast, valued combined changes in the existing bag limit and size limit. The biological component of the stated preference model deemed such change necessary to ensure a sustainable stock. The biological model provides an economic constraint and results in the treatment of the bag and size limits as a composite good in which separate utilities cannot be measured for each component of the composite good. The stated preference choice method (SPCM) was used to estimate the change in economic value by boat mode of access (e.g., charter boat and private boat). The models also controlled for length of trip (full day versus half-day) for charter boat trips and for type of day (weekend or weekday) for both boat modes of access. Since those who accessed the fishery by private boat had a lower probability of achieving the bag limit/size limit, a model was run to predict the probability of achieving the bag limit/size limit and the probability was interacted with the bag limit/size limit choice. This yielded a positive willingness to pay for the bag limit/size limit combination that was sustainable. Estimated values per person per day for changing the bag limit/size limits to a sustainable level were USD 20.24 for the charter boat mode and USD 32.54 for the private boat mode. Aggregating this to a total value change using a five-year annual average (2012–2016) of total days of fishing for spotted seatrout on Florida’s West Coast yielded an estimate of USD 147.9 million per year for charter boat anglers. The total annual value was about USD 3.4 million, while for private boat anglers the annual value was about USD 144.5 million.

Determinants of Residents’ Willingness to Pay for Water Quality Improvements in Haikou, China: Application of CVM and ISM Approaches

Exploring the determinants of residents’ willingness to pay (WTP) for water quality improvements is essential for protecting the water quality and formulating effective governance policies. This paper applies the double-bounded dichotomous contingent valuation method (CVM) to determine residents’ WTP for water quality improvements, calculate the average annual willingness of Haikou residents to pay for water quality improvements, and explore the factors influencing residents’ WTP for water quality improvements. Interpretive structural modeling (ISM) is then used to further analyze the association and hierarchy between the influencing factors. The results show that (1) Residents are willing to pay an average of 28.42 RMB/household/year for water quality improvements, and the total annual value of water quality improvements in Haikou is at least 5.58 × 108 RMB; (2) age, education level, income level, minor family member and government trust are the main factors that significantly (p < 0.05) influence urban residents’ WTP; (3) among the factors identified as significantly affecting WTP, the deeper root factors include educational attainment, age, and ultimately, the willingness of residents to participate in water quality improvements through indirect factors (government trust, income level, presence of minors). This study allows an in-depth and detailed understanding of the determinants of residents’ WTP for water quality improvements and provides a practical and relevant guide to water quality improvements in the tropics.

An assessment of recreational values of Dibru-Saikhowa National Park, Assam using Travel Cost Method

Dibru-Saikhowa National Park (DSNP) comprises 340 km2 of core zone of Dibru-Saikhowa Biosphere Reserve in Assam, India. DSNP receives on average 3000-3500 tourists every year. Most of the visitors were on independent holidays often coming to the DSNP. Most of the visitors coming from outside the northeastern states are coming to DSNP as the second destination after the Kaziranga National Park, which is about 300 km from the DSNP. Recreational value of DSNP was estimated by using Travel Cost Method. Results show that the average consumer surplus per tourist per visit accruing to domestic tourists was Rs. 2892.50 and total annual recreational value of the DSNP was Rs. 10.11 million which is almost 40 times the total revenue (Rs. 2.50 lakh) earned by the DSNP in a year. This clearly shows that revenue collected through entry fee is not reflecting the true economic value of recreational services of the DSNP. The results of the study provide enough justification for enhanced investment from government in the DSNP to ensure continued flow of essential ecosystem services.

개별여행비용법을 이용한 강원도 삼척 맹방 해수욕장의 경제적 가치추정

The purpose of this paper is to estimate the economic value of coastal beaches in Samcheok Maengbang of Kangwon Province. ITCM(Individual Travel Cost Method) is applied to estimate the economic value of its beaches using Poisson, negative binomial, truncated Poisson and truncated negative binomial models. The consumer surplus during length of stay per capita is estimated to be 173,790~203810 won in beaches, and the consumer surplus per person and per day 68,280~80,080 won. Annual total economic value of its beaches considering the number of visitors in beaches can be converted to be 65,516 million won.