Analysis of the Carrying Capacity and the Total Maximum Daily Loads of the Karang Mumus Sub-watershed in Samarinda City Using the WASP Method

Watershed is a multi-aspect ecological system, which functions as a source of water resources, in order to meet daily needs. It also motivates both economical and life matters, as well as serve as a sanitary channel for the surrounding community. Watershed also generates pollutants, which are known to potentially cause a decrease in river water quality. The degradation of river habitats that are caused by high pollutants penetration into the water body, decreases the capacity to carry out self-purification of toxic loads. The water pollutant load-carrying capacity is then calculated through various methods, one of which is the use of a computerized numerical modeling simulation called WASP (Water Quality Analysis Simulation Program). This method was developed by the ES-EPA, in order to process TMDLs (Total Maximum Daily Loads) data on river bodies, as well as examine each part of the water quality, based on spatial and temporal inputs. This study was conducted at the Karang Mumus Sub-watershed flowing through the centre of Samarinda City, with aims to determine the pollutants' carrying capacity, existing load, and toxic waste allocation, via the use of the BOD (Biological Oxygen Demand) technique as a parameter of water quality. The calculation was carried out by segmenting the river into five parts, based on the number of districts it passes through, during pollutant loads inventory. The WASP modeling simulation showed that the total pollutant load-carrying capacity of the whole segments was 5,670 kg/day. It also showed the existing loads of about 3,605 kg/day, with the margin having the ability to receive pollutants at 2,065 kg/day. Moreover, the allocation of pollutant loads varies for each segment, with 2, 3, and 4 observed to reduce the pollutant by 390, 220, and 10 kg/day, respectively. However, segments 1 and 5 were still allowed to receive pollutant loads up to 1,740 and 945 kg/day, respectively.

Water quality measurements in Buzzards Bay by the Buzzards Bay Coalition Baywatchers Program from 1992 to 2018

The Buzzards Bay Coalition’s Baywatchers Monitoring Program (Baywatchers) collected summertime water quality information at more than 150 stations around Buzzards Bay, Massachusetts from 1992 to 2018. Baywatchers documents nutrient-related water quality and the effects of nitrogen pollution. The large majority of stations are located in sub-estuaries of the main Bay, although stations in central Buzzards Bay and Vineyard Sound were added beginning in 2007. Measurements include temperature, salinity, Secchi depth and concentrations of dissolved oxygen, ammonium, nitrate + nitrite, total dissolved nitrogen, particulate organic nitrogen, particulate organic carbon, ortho-phosphate, chlorophyll a, pheophytin a, and in lower salinity waters, total phosphorus and dissolved organic carbon. The Baywatchers dataset provides a long-term record of the water quality of Buzzards Bay and its sub-estuaries. The data have been used to identify impaired waters, evaluate discharge permits, support the development of nitrogen total maximum daily loads, develop strategies for reducing nitrogen inputs, and increase public awareness and generate support for management actions to control nutrient pollution and improve water quality.

Total maximum daily loads of beton reservoir, Gunungkidul Regency, Indonesia during the rainy season

A total maximum daily load (TMDL) is an integrated mechanism to maintain water body to meet the water quality standards of its designated uses. This research was intended to determine the TMDL of Beton Reservoir, a structure built to regulate the water discharge of Beton karst spring in Gunungkidul, Indonesia, especially during the rainy season. The TMDL calculation referred to the Regulation of the Minister of State for Environment No. 28 of 2009 on TMDLs of Lakes and/or Reservoirs that required a calculation of morphological and hydrological characteristics, and water quality to meet Class II standard issued in the Regulation of the Governor of the Special Region of Yogyakarta No. 20 of 2008. The results showed that Beton Reservoir had a total volume of 22 586.83 m3, a surface area of 18 673.12 m2, and a depth of averagely 1.21 m and released water at a rate of 0.48 m3 s–1. From the perspective of quality, the TSS and DO of its water had exceeded the standards, whereas the other parameters: temperature, TDS, pH, BOD, COD, total PO4, and NO3 were within their allowable presence in the water. Based on TMDLs for TSS, DO, BOD, COD, total PO4, and NO3, the Beton Reservoir can no longer accommodate TSS and NO3 while continuing to meet the standards for these pollutants. High levels of TSS and NO3 are attributable to the agricultural activities taking place on the catchment and the flow concentration typical of karst regions.

Response to Comments for “An Ecological Function Approach to Managing Harmful Cyanobacteria in Three Oregon Lakes: Beyond Water Quality Advisories and Total Maximum Daily Loads (TMDLs)”, Water 2019, 11, 1125

The commenter’s key argument is that Diamond Lake’s problem is strictly one of biomass, i.e., introduction of the invasive Tui Chub fish. There are a few things to note in that respect. The Tui Chub is a bait fish. It is a lower-order prey fish for higher-order trout/salmonid species. Tui Chub is zooplanktivorous. Since the Tui Chub feed on zooplankton, if they themselves are prey for other species (or are being “culled” by artificial means), and there is no other entity to feed on the plankton and algae, the result would be a mass of plankton/algae bloom (i.e., harmful algal blooms (HABs)). This would lead to anoxic conditions in the euphotic zone, which puts even more stress on the higher-order trout/salmonid species. Our work found that the biological community (i.e., invertebrates and fish) are lagging indicators (i.e., response indicators).

Harmful Cyanobacteria in Three Oregon Lakes: Comments on Hall et al. Beyond Water Quality Advisories and Total Maximum Daily Loads (TMDLs). Water 2019, 11, 1125

The article “An Ecological Function Approach to Managing Harmful Cyanobacteria in Three Oregon Lakes: Beyond Water Quality Advisories and Total Maximum Daily Loads (TMDLs), Water 11:1125” by Hall et al. critiques the current approach used by the state of Oregon with regard to managing cyanobacterial blooms and offers the proper functioning condition (PVC) as a superior method of managing cyanobacterial blooms in lakes derived from nonpoint sources of pollution. They evaluated three lakes in Oregon as examples of how this approach could be applied to support water quality improvement. Two of the three lakes, Lemolo and Diamond, experienced cyanobacterial blooms, not as a function of nonpoint source loadings from the watershed, but rather because of internal nutrient cycling associated with high fish biomass. The third lake, Tenmile Lakes, in additional to having a greatly altered fish community, also experiences cyanobacterial blooms (CyanoHABs) issues because of timber harvest on steep slopes, loss of wetlands, altered watershed hydrology and nutrient input from septic systems. The authors’ attempts to use satellite images and PVC methodology on the stream networks is incomplete with respect to Tenmile Lakes and is totally misdirected regarding Lemolo and Diamond Lakes. Although I don’t support the current system employed by the state of Oregon to manage lakes experiencing CyanoHABs issues, the proposed approach offered by staff with the U.S. Environmental Protection Agency will yield little water quality benefit for the lakes in question.