Mean Total Suspended Solids Research Articles

Characterization of solid wastes from sablefish (Anoplopoma fimbria) in intensive culture

Sablefish (Anoplopoma fimbria) is a Pacific marine species that adapts well to aquaculture, grows extremely fast, and command a high market price. Because of environmental and regulatory concerns, increased production of this species is likely to occur in land-based systems. Little is known about the waste production characteristics of sablefish, information that will have a critical impact on the design of aeration, solid removal, and biofilter design for this species. It was found that the concentration of total suspended solids (TSS) in the effluent was extremely low and the mean TSS ranged from 0.9 to 1.7 mg/L. Compared to other important culture fish, sablefish produce significantly less fecal solids (5.2–7.9 % based on feed inputs) and less of their solids settled out (57.3–65.8 % of total suspended solids). TSS production following feeding of a special feed for reuse systems was significantly higher (51.9 %) compared to fish fed a conventional diet. The reduced production of TSS by sablefish is due to higher apparent digestibility coefficients and possible production of wastes that are not retained on the standard filter used for TSS analysis. Additional rinsing of the filters to remove salt and the use of large sampling volumes can significantly improve the accuracy of TSS analysis for marine culture species.

Climate change intensifies algal biomass resurgence in eutrophic Lake Taihu, China

Climate change can significantly alter phytoplankton growth and proliferation, which would counteract restoration efforts to control algal blooms. However, the knowledge is limited about the quantitative evaluation of the causal effect of algal biomass resurgence in large shallow lakes where there is no significant improvement after long term lake restoration. Here, a bucket process-based phytoplankton dynamic model is developed to quantify the contributions of climate change and nutrients concentration changes to phytoplankton biomass resurgence after 2014 in hypereutrophic Lake Taihu, China. Compared to 2008–2014, the mean water temperature (WT) and the mean phosphate are higher, the mean photosynthetically active radiation (PAR), the mean total suspended solids (TSS), and the mean dissolved inorganic nitrogen (DIN) are lower, during 2015–2020. Their contribution to algal biomass resurgence during 2015–2020 is WT (+58.7 %), PAR (−2.6 %), TSS (+23.2 %), DIN (−22.1 %) and phosphate (+42.7 %), respectively. Climate change (WT, PAR, and TSS), which contributed +64.9 % to the phytoplankton biomass resurgence, underscores the urgent need to continuously take more effective measures to reduce nutrient emissions to offset the effects of climate change in Lake Taihu and in other eutrophic lakes.

Impact of flow pathway and source water connectivity on subsurface sediment and particulate phosphorus dynamics in tile-drained agroecosystems

Subsurface tile drainage is recognized as a significant source of sediment and particulate phosphorus (PP) in the midwestern U.S. However, the role of subsurface flow pathway and source water connectivity dynamics on sediment transport is poorly understood. The overarching objective of this study was to investigate sediment and PP loading dynamics for a midwestern subsurface tile drained agroecosystem and assess the governing flow pathway and water sources impacting subsurface sediment loads. In this study, we used a recently-developed framework that couples event-based hydrograph recession and specific conductance-end-member mixing analysis (SC-EMMA) to assess governing drivers of sediment transport through tile. We collected high-frequency specific conductance, turbidity, and subsurface discharge data from an edge-of-field (EOF) tile main located in northwestern Ohio for 15 months. Multiple linear regression (MLR) analysis and hysteresis analysis were employed to evaluate the impact of pathway-connectivity dynamics on flow-weighted mean Total Suspended Solids (TSS) concentrations. The MLR analysis showed that quickflow of new water (Qquick-new) had the highest flow-weighted mean sediment concentrations, and that concentrations associated with quickflow of old water (i.e., matrix-macropore exchange) were variable. Analysis using the hysteresis index (HI) showed that hysteresis characteristics (magnitude and direction) for separated hydrographs using the pathway-connectivity framework deviated from HI values of subsurface discharge (Qtile) and highlighted the importance of Qquick-new through much of the monitoring period. For events immediately following tillage and cover crop application in Fall 2019, we found Qquick-old was the primary form of preferential flow, peak sediment concentrations coincided with Qquick-old, and event sediment loadings during these events decreased relative to the previous fall. The findings suggest that reducing preferential transport of new water may be an effective strategy for reducing sediment and particulate P loadings at the edge-of-field.

Impact of Irrigational Runoff on Fish Biodiversity in River Ngadda, Maiduguri – Borno State

Irrigation is a dry season agricultural activity that was known to man for centuries. Agricultural runoff has been identified as the major nonpoint sources of pollution into surface waterbodies which changes the physico – chemical parameters thereby impacting on the biodiversity of such ecosystem. River Ngadda receives pollutants from the irrigational sites along the river bank. The study was aimed at assessing the impact of irrigation on fish biodiversity in river Ngadda, Maiduguri, Borno State, Nigeria. The objectives of the study were to determine the physico – chemical parameters and examine the fish biodiversity of the river. The river was divided into 4 sampling Stations. Water samples was collected biweekly for the period of 6 months from 4 sampling stations. The physico – chemical qualities (total nitrogen (TN), ammonium (NH4+), total phosphorus (TP), total organic carbon (TOC), total dissolved solids (TDS), turbidity (Tur) and total suspended solids (TSS) were determined using standard methods. Capture and recapture method was employed to determine the relative abundance of fish species using Lincoln index. The mean Total Nitrogen (TN) ranges from 5.02 mg/L – 8.31mg/L, mean ammonium (NH4+) ranges from 0.93mg/L – 2.01, mean Total phosphorous (TP) ranges from 0.07mg/L – 1.81mg/L. mean Total Organic Carbon (TOC) ranges 5.87mg/L – 7.45mg/L, mean Turbidity (Tur) ranges from 27mg/L – 31mg/L, mean Total Dissolved Solids (TDS) ranges 198NTU – 298NTU, mean Total Suspended Solids ranges from 34mg/L – 47mg/L and mean surface water Temperature ranges from 26°C – 28°C. A total of 4 families and 10 species of fishes were identified in the sampling stations.

Analysis of Suspended Sediment in the Anavilhanas Archipelago, Rio Negro, Amazon Basin

This article analyzes the flows of water and total suspended sediment in different reaches in the lower course of the Negro River, the largest fluvial blackwater system in the world. The area under study is the Anavilhanas Archipelago, which is a complex multichannel reach on the Negro River. Between the years 2016 and 2019, data about water discharge, velocity, and concentration of total suspended solids (TSS) were acquired in sample sections of the Negro River channels located upstream, inside, and downstream of the Anavilhanas Archipelago. In the study area, the Negro River drains an area greater than 700,000 km2, and the mean water discharge observed before the Anavilhanas was about 28.655 m3·s−1, of which 97% flows through two channels of the Archipelago close to the right and left banks. The mean TSS concentration of the Negro River upstream and downstream the Archipelago was 3.28 mg·L−1 and 1.63 mg·L−1, respectively. Within the Archipelago, we observed more TSS in the channel on the left bank of the Negro River (mean of 4.50 mg·L−1). The total suspended sediment discharge of the Negro River before (3.14 Mt·year−1) and after (1.43 Mt·year−1) the Anavilhanas Archipelago indicates a 55% retention of the suspended load due to the low water slope and reduced flow velocity caused by the backwater effect of Solimões River on the Negro River. The hydro-sedimentary scenario of the low course of the Negro River characterized in this study indicates a slow and continuous sedimentation process in the Anavilhanas Archipelago. The results presented will serve as a baseline to assess the impacts of the dams on the Branco River, the main tributary for both water and sediment in the Negro River basin.

Impacts of Tile Drainage on Phosphorus Losses from Edge-of-Field Plots in the Lake Champlain Basin of New York

Quantifying the influence of tile drainage on phosphorus (P) transport risk is important where eutrophication is a concern. The objective of this study was to compare P exports from tile-drained (TD) and undrained (UD) edge-of-field plots in northern New York. Four plots (46 by 23 m) were established with tile drainage and surface runoff collection during 2012–2013. Grass sod was terminated in fall 2013 and corn (Zea mays L.) for silage was grown in 2014 and 2015. Runoff, total phosphorus (TP), soluble reactive phosphorus (SRP), and total suspended solids (TSS) exports were measured from April 2014 through June 2015. Mean total runoff was 396% greater for TD, however, surface runoff for TD was reduced by 84% compared to UD. There was no difference in mean cumulative TP export, while SRP and TSS exports were 55% and 158% greater for UD, respectively. A three day rain/snowmelt event resulted in 61% and 84% of cumulative SRP exports for TD and UD, respectively, with over 100% greater TP, SRP and TSS exports for UD. Results indicate that tile drainage substantially reduced surface runoff, TSS and SRP exports while having no impact on TP exports, suggesting tile drains may not increase the overall P export risk.

Influence of feedlot manure amendments on runoff hydrology and sediment loss during transition between continuous and legacy phases

Little research has been conducted on the effect of beef feedlot manure amendments on runoff hydrology and soil loss during the transition between continuous and legacy application phases. We conducted a 6 yr (2013–2018) study and utilized surface (0–5 cm) soil collected from a long-term (since 1998) field experiment on a clay loam soil in southern Alberta, Canada. The treatments were stockpiled or composted feedlot manure with straw (ST) or wood-chip (WD) bedding applied at 13, 39, and 77 Mg ha−1 (dry weight). There was also an unamended control and inorganic fertilized treatment (IN). Disturbed surface soil was collected from all treatments after 15 (C15), 16 (C16), and 17 (C17) continual annual applications (2013–2015), and then 1 (L1), 2 (L2), and 3 (L3) yr (2016–2018) after manure applications were discontinued in 2015. The soil was packed into runoff trays, and a Guelph rainfall simulator (70 mm h−1) was used to generate 30 min of runoff. The time to runoff, total runoff depth, and flow-weighted mean concentrations (FWMCs) and mass loads of total suspended solids (TSS) were determined. Mean values of runoff variables were significantly greater for ST than WD in certain years for time to runoff (by 28%–127%), runoff depth (44%), TSS FWMCs (58%–137%), and FWMC loads (28%–230%). Mean TSS was generally significantly greater at the two lower than highest manure rates for FWMC (48%–135%) and loads (21%–253%). Overall, choice of bedding material showed the most potential to maximize infiltration and reduce water and sediment loss.

Siltation load contribution of nickel laterite mining on the coastal water quality of Hinadkaban Bay, Surigao Provinces, Philippines

Satellite images of Hinadkaban Bay, in Surigao Provinces, Philippines have indicated quite extensive siltation. Apparently, hilltop mining operations and other anthropogenic activities have resulted to deposition of suspended solids into the stretch of Hinadkaban Bay. In this regard, a multidisciplinary team was dispensed to undertake study in line with determining the environmental conditions along Hinadkaban Bay. Coastal marine water samples and surface water samples were obtained in two separate occasions (March and October 2012) via grab sampling. It was found that soil erosion in the study area was exacerbated by mining operations, road constructions and other anthropogenic activities, with heavy siltation often observed in areas near causeways, stockyards or siltation ponds of mine companies. Mean total suspended solids data of 5.87 mg/L was obtained for samples collected during the dry season while as high as 1000 mg/L TSS was recorded during heavy runoff. Meanwhile, average concentration of total nickel in water samples ranged from 0.050 μg/mL during dry season to 0.25 μg/mL during wet season. On the other hand mean total chromium concentration ranged from 0.060 μg/mL (dry season) to 0.30 μg/mL (wet season). Results of this study shall contribute to the effort of protecting surface water resources and of optimizing their beneficial uses.

A spatially distributed model for assessment of the effects of changing land use and climate on urban stream quality

AbstractWhile the effects of land use change in urban areas have been widely examined, the combined effects of climate and land use change on the quality of urban and urbanizing streams have received much less attention. We describe a modelling framework that is applicable to the evaluation of potential changes in urban water quality and associated hydrologic changes in response to ongoing climate and landscape alteration. The grid‐based spatially distributed model, Distributed Hydrology Soil Vegetation Model‐Water Quality (DHSVM‐WQ), is an outgrowth of DHSVM that incorporates modules for assessing hydrology and water quality in urbanized watersheds at a high‐spatial and high‐temporal resolution. DHSVM‐WQ simulates surface run‐off quality and in‐stream processes that control the transport of non‐point source pollutants into urban streams. We configure DHSVM‐WQ for three partially urbanized catchments in the Puget Sound region to evaluate the water quality responses to current conditions and projected changes in climate and/or land use over the next century. Here, we focus on total suspended solids (TSS) and total phosphorus (TP) from non‐point sources (run‐off), as well as stream temperature. The projection of future land use is characterized by a combination of densification in existing urban or partially urban areas and expansion of the urban footprint. The climate change scenarios consist of individual and concurrent changes in temperature and precipitation. Future precipitation is projected to increase in winter and decrease in summer, while future temperature is projected to increase throughout the year. Our results show that urbanization has a much greater effect than climate change on both the magnitude and seasonal variability of streamflow, TSS and TP loads largely because of substantially increased streamflow and particularly winter flow peaks. Water temperature is more sensitive to climate warming scenarios than to urbanization and precipitation changes. Future urbanization and climate change together are predicted to significantly increase annual mean streamflow (up to 55%), water temperature (up to 1.9 °C), TSS load (up to 182%) and TP load (up to 74%). Copyright © 2016 John Wiley & Sons, Ltd.

Turbidity and Total Suspended Solids on the Lower Cache River Watershed, AR.

The Cache River Watershed (CRW) in Arkansas is part of one of the largest remaining bottomland hardwood forests in the US. Although wetlands are known to improve water quality, the Cache River is listed as impaired due to sedimentation and turbidity. This study measured turbidity and total suspended solids (TSS) in seven sites of the lower CRW; six sites were located on the Bayou DeView tributary of the Cache River. Turbidity and TSS levels ranged from 1.21 to 896 NTU, and 0.17 to 386.33mg/L respectively and had an increasing trend over the 3-year study. However, a decreasing trend from upstream to downstream in the Bayou DeView tributary was noted. Sediment loading calculated from high precipitation events and mean TSS values indicate that contributions from the Cache River main channel was approximately 6.6 times greater than contributions from Bayou DeView. Land use surrounding this river channel affects water quality as wetlands provide a filter for sediments in the Bayou DeView channel.

Reclaimed Water Filtration Efficiency and Drip Irrigation Emitter Performance with Different Combinations of Sand and Disc Filters

AbstractFilters are the most important components in micro‐irrigation systems, in particular for filtering high levels of suspended solids in reclaimed water. An experiment was conducted using reclaimed water to evaluate the removal efficiencies of sand filters with different uniformity coefficients (UCS) and in combination with sand filters with a 130 µm disc filter (120‐mesh). The treatment effects on emitter discharge were also investigated in this study. The results showed that the sand filters exhibited removal efficiencies of 11.4–48.0%, increasing to 30.7–80.3% when combined with the disc filter. The sand filter removal efficiency decreased with increase of the media diameter. A linear‐plateau relationship was observed between the removal efficiency and UCS. Compared to the control group, the combined filters reduced emitter clogging and significantly prevented a decrease in emitter discharge. It is suggested using the equivalent diameter, dt, to represent the filter medium diameter instead of using the effective diameter, de. The recommended value for the sand filter UCS > 2.0 for a mean total suspended solids (TSS) of 17.5 ± 12.7 mg l−1. Copyright © 2015 John Wiley & Sons, Ltd.

Operation of an integrated algae pond system for the treatment of municipal sewage: a South African case study.

Integrated algae pond systems (IAPS) combine the use of anaerobic and aerobic bioprocesses to effect sewage treatment. In the present work, the performance of IAPS was evaluated to determine the efficiency of this technology for treatment of municipal sewage under South African conditions. Composite samples were analysed over an 8 month period before and after tertiary treatment. Spectrophotometric assays indicated that the treated water from this IAPS was compliant with the discharge limits for phosphate-P, ammonium-N and nitrate/nitrite-N, and mean values were: 5.3, 2.9 and 12.4 mg L(-1), respectively. Chemical oxygen demand (COD), however, fluctuated significantly and was dependent on full function of the IAPS. Mean COD of the final treated water was 72.2 mg L(-1). Although these results suggest that the treated water discharged from this IAPS operating under South African conditions meets the standard for discharge, mean total suspended solids (TSS) was routinely above the limit at 34.5 ± 13 mg L(-1) and faecal coliforms were higher than expected. Tertiary treatment using a maturation pond series (MPS), slow sand filtration (SSF), or a controlled rock filter (CRF) ensured that the final treated water from the IAPS was of a quality suitable for discharge to the environment with CRF > SSF > MPS.

Estimating Suspended Solids from Turbidity in the Robeson Creek, NC Watershed

AbstractThe purpose of this project was to assess the effect of estimating total suspended solids (TSS) concentrations from turbidity on TSS loads for streams in the Robeson Creek watershed. Discharge was monitored continuously and base‐flow grab and storm event composite samples were collected and analyzed for TSS and turbidity from five sites during five years of monitoring. For base‐flow samples, the TSS‐turbidity relationship for all five sites was poor indicating that TSS concentrations in base flow cannot be estimated from a TSS‐turbidity relationship. To test the effect of analyzing fewer samples, TSS from every third and the first 20 samples collected from each site was used to develop TSS‐turbidity relationships. In addition, the TSS‐turbidity relationship developed from the most downstream site was used to estimate TSS concentrations from turbidity measured at the other four sites. For four of the five sites, analyzing every third sample for TSS and using the TSS‐turbidity relationship to estimate the missing TSS concentrations would result in mean TSS loads that were not significantly different from the observed. Using the TSS‐turbidity relationship from the outlet to estimate TSS from turbidity measured at the other four sites resulted in significantly different mean TSS loads at three of the four sites. These results indicate that estimating TSS concentrations from turbidity using a TSS‐turbidity relationship developed from a subset of the overall dataset should be done with great caution.

Assessment of Car Wash Runoff Treatment Using Bioretention Mesocosms

Car wash runoff is known to be a pollution source to surface water bodies. Many groups hold car-washing fundraisers unaware of pollution issues associated with car wash runoff. This preliminary study investigated whether rain gardens are an appropriate management practice for reducing car wash pollutants, specifically surfactants. The concentrations of total phosphorus (TP), total suspended solids (TSS), and surfactants were measured in car wash runoff before and after treatment in three rain garden mesocosms. Mean TSS and surfactant effluent concentrations were significantly lower than the car wash runoff with TSS reductions ranging from 84 to 95% and surfactant reductions ranging from 89 to 96%. The removal efficiencies for surfactants were not enough to reduce concentrations below literature-based values for aquatic toxicity. Mean TP effluent concentrations were higher than the car wash runoff with increases ranging from 197 to 388%, although the increase was not statistically significant. This project demonstrates the potential for using bioretention to reduce pollutants associated with car wash runoff and using car wash events to educate the public about watershed protection.

Spatial and temporal variability of turbidity, dissolved oxygen, conductivity, temperature, and fluorescence in the lower Mekong River–Tonle Sap system identified using continuous monitoring

Continuous monitoring of turbidity, dissolved oxygen (DO), conductivity, temperature, and fluorescence was done at five locations on the Tonle Sap Lake and the Mekong–Bassac Rivers near Phnom Penh, Cambodia, between 2004 and 2010 using autonomous datasondes. Seasonal, daily, and spatial trends were clearly identified in the data and were related to the annual monsoon rainy season–dry season cycle, system metabolism, system hydraulics, and in some cases, localized phenomena such as waste discharges. The datasondes were particularly useful to track the oxygenation of anoxic black water areas in the flooded forest fringe of the Tonle Sap that occurred during the rainy season freshwater pulse. A strongly developed vertical variation of turbidity, DO, and conductivity in the flooded forest fringe may be related to a combination of factors, including dissolved material release from bed sediment and a floating organic-rich particulate layer near the bottom of the lake. Grab samples for total suspended solids (TSS) were collected at the Preak Leap (PL) site (Mekong River) in 2009 and 2010. An excellent relationship was established between daily mean turbidity and TSS concentration for the PL site, with r 2 = 0.95. Autoregressive, integrated, moving average models adequately forecast water level and water quality data one month ahead.

Runoff water quality and vegetative establishment for groundcovers on steep slopes

Construction sites can be a major source of sediment, a common pollutant in surface waters, because steep slopes are often bare during active construction. The use of mulch and polymers has been found to reduce erosion rates and improve runoff water quality on construction sites. Different erosion control methods on steep slopes (2:1) consisting of straw, straw plus 37 kg ha−1 (33 lb ac−1) linear anionic polyacrylamide (straw + PAM), and excelsior blankets were evaluated based on runoff water quality, vegetative establishment, or both at six construction sites. Plots (3 to 9 m [10 to 30 ft] wide by 9 m [29.5 ft] long) were established on cut slopes. Runoff was collected at four of six sites by installing plastic barriers to direct a portion of runoff into containers, later analyzed for turbidity and total suspended solids (TSS) in the laboratory. Large differences in water quality were often not statistically significant for individual storms due to high variability. However, when data were averaged across all storm events, the straw + PAM treatment reduced mean runoff turbidity at three of four sites and mean TSS at two of the four sites compared to straw alone. Maximum reductions in turbidity and TSS were 81% and 56%, respectively. Runoff from the excelsior plots had significantly lower turbidity and TSS than straw plots in one of three sites. Compared to straw + PAM, excelsior had significantly higher turbidity at two of three sites and higher TSS at one of three sites. All differences among treatments for individual storm events occurred within the first three events. Vegetative cover was determined in the field, and aboveground vegetation was harvested to determine biomass production. Neither vegetative cover nor biomass were affected by treatment, and average cover was 60% or less for five of the six sites. Rainfall patterns were largely responsible for vegetative growth, with heavier rainfall soon after seeding tending to reduce cover.

시화호 유역 비점오염물질의 유출특성 및 부하량 연구

본 연구에서는 시화호로 유입되는 다양한 비점오염원 중 도심유역을 흐르는 안산천 및 화정천과 산업지역인 반월산단 토구를 통한 강우유출수 내 총부유물질, 화학적산소요구량, 용존영양염, 총인 및 총질소 등의 비점오염물질의 유출특성 및 총유출부하량을 조사하였다. 조사지역 및 조사 시기에 따라 차이는 있으나 강우 시작 후 비점오염물질의 농도가 증가한 뒤 감소하는 경향을 보였다. 총부유물질의 평균농도는 안산천이 315 ㎎/L로 가장 높았으며 반월산단 토구에 비해 약 2~5배 정도 높았으나 화학적산소요구량, 총인 및 총질소의 평균농도는 반월산단 토구가 도심하천에 비해 높은 것으로 나타났다. 총부유물질은 화학적산소요구량 및 총인과 양의 상관성을 보였으며 용존영양염과는 음의 상관성을 나타냈다. 반월산단 토구를 통한 비점오염물질의 총유출량은 토구의 유역면적에 비례하였으며 가장 유역면적이 넓은 3토구에서의 비점오염물질의 유출량이 가장 높았다. 조사기간 내 약 30시간 동안 반월산단토구를 통하여 총부유물질 187,536 ㎏, 화학적산소요구량 17,118 ㎏, 총인 922 ㎏, 총질소 13,519 ㎏의 비점오염물질이 유출되는 것으로 나타났다. 반월공단 토구 유역면적은 전체 시화호 소유역 중 3%를 차지하는 것을 고려할 때 막대한 양의 비점오염물질이 별다른 처리과정 없이 시화호로 직접 유출되고 있음을 알 수 있었다. 이러한 강우시 비점 오염물질의 유출은 시화호 수질을 더욱 악화 시킬 것이기 때문에 비점오염원 관리 및 저감대책이 시급하게 요구되며 본 연구결과는 향후 시행예정인 시화호 연안오염총량제의 비점오염 최적관리기법 개발에 유용한 정보를 제공하고 있다.

Suspended Solids in and Turbidity of Runoff from Green Roofs

Green roof technology is used to reduce the quantity of stormwater runoff, but questions remain regarding its impact on quality. This study analyzed the total suspended solids (TSS) in and the turbidity of runoff from green roof growth media mixed with composted pine bark in an indoor pot study. The results showed that there were elevated levels of TSS and turbidity in the runoff that decreased over time for all growth media. Both TSS and turbidity are affected by the type of growth media. Lava and haydite had higher mean TSS and mean turbidity than arkalyte and bottom ash. Vegetation reduced the mean turbidity and mean TSS of the first flush by an average of 53% and 63%, respectively, but generally had no statistically significant effect thereafter. The results indicate that the media, rather than the vegetation, has a greater effect on TSS and turbidity in the runoff. In areas with stringent water quality regulations for stormwater runoff from developed sites, media selection may be an important consideration. It may also be necessary in these regions to ensure that the roof is planted prior to receiving rainfall to minimize the first flush effect and that any irrigation does not result in runoff.

Remote sensing analysis of rainstorm effects on sediment concentrations in Apalachicola Bay, USA

Remote sensing of total suspended solids (TSS) by satellite techniques in estuaries and bays plays an important role in monitoring water quality over a large area. It is valuable to the management of coastal water environment and ecosystems. In this study, remote sensing mapping of TSS was conducted to investigate the effects of rainstorm events on Apalachicola Bay. A rainstorm event (October 7–8, 2008) was selected for a period when wind speeds were weak and the river inflow was almost steady. TSS mapping of MODIS images before and after the rainstorm event showed substantial increase of TSS induced by the rainstorm. Using an image during low river discharge before the rainstorm as a reference, TSS distribution was mapped by an improved regression model using MODIS image after a rainstorm event. Two thresholds of TSS (25 and 60 mg l − 1 ) were applied to delineate the rough edge of the sediment plume. The boundary separating highly turbid and relatively clear water was near Sikes Cut. The event did not influence the East Gulf Beach in the west side of East Pass. The study also shows the surface TSS concentrations can get back to their reference values (mean TSS at about 17 ~ 20 mg l − 1 and maximum TSS at about 70 mg l − 1 ) after 60 h and 50 min (i.e. almost the day 2.5) of rainstorm stopping. The method developed can be used to monitor sediment load to support estuarine ecological research and water quality assessment in Apalachicola Bay.

Field Evaluation of Four Level Spreader–Vegetative Filter Strips to Improve Urban Storm-Water Quality

An assessment of the performance of four level spreader–vegetative filter strip (LS-VFS) systems designed to treat urban storm-water runoff was undertaken at two sites in the Piedmont of North Carolina. At each site, a 7.6-m grassed filter strip and a 15.2-m half-grassed, half-forested filter strip were examined. Monitored parameters included rainfall, inflow to, and outflow from each LS-VFS system. A total of 21 and 22 flow-proportional water quality samples were collected and analyzed for the Apex and Louisburg sites, respectively. All studied LS-VFS systems significantly reduced mean total suspended solids (TSS) concentrations (p<0.05), with the 7.6 and 15.2-m buffers reducing TSS by at least 51 and 67%, respectively. Both 15.2-m VFSs significantly reduced the concentrations of total Kjeldahl nitrogen (TKN), total nitrogen (TN), organic nitrogen (Org-N), and NH4-N (p<0.05), whereas results were mixed for the 7.6-m VFSs. Significant pollutant mass reduction was observed (p<0.05) for all nine pollutant f...