Water-quality response to changes in phosphorus loading of the Winnebago Pool Lakes, Wisconsin, with special emphasis on the effects of internal loading in a chain of shallow lakes

ABSTRACT Sediments are important to nutrient dynamics, especially due to phosphorus internal loading. Several studies have observed that internal loading could prevent water quality from improving in lakes, even when external phosphorus loading is significantly decreased. Therefore, there is an urgent need to assess the potential release of phosphorus contained in the sediment, and thus, its potential to impact water quality. In this study, the vertical and horizontal distributions of distinct phosphorus forms in the bottom sediments of artificial reservoirs, located at Forquilha watershed (Ceará, Brazil), were investigated through sequential chemical fractionation. The reservoirs Lagoa Cercada (R#1), Riacho do Algodão (R#2), Riacho Verde (R#3), Cachoeira (R#4), Chagas Manu (R#5), Quandu (R#6) and Balanças (R#7) were investigated. Reservoirs R#1 (most downstream reservoir of the watershed) and R#7 (most upstream reservoir of the watershed) had higher concentrations of total phosphorus (PT) and lower pH values, potentially exerting greater influence in phosphorus concentration in the water column. Reservoirs R#3 and R#4 presented a predominance of residual phosphorus (PRe), the least available fractions of phosphorus and thus, presented a lower potential for internal loading. Reservoirs R#5, R#1 and R#2 showed a tendency of decreasing total phosphorus (PT) as the sediment depth increased, probably indicating an increase of allochthonous phosphorus loading along time. Reservoir R#6 showed the predominance of PFeAl and PCa fractions on points A and B, respectively, showing that the characteristics of the sediments may vary in the same reservoir. Mobile (PM) and iron and aluminum-bound phosphorus (PFeAl) were the least and the most abundant fractions in most of the samples analyzed, respectively.

Download Full-text

Evaluating the factors responsible for post-fire water quality response in forests of the western USA

International Journal of Wildland Fire ◽

10.1071/wf18191 ◽

2019 ◽

Vol 28 (10) ◽

pp. 769 ◽

Cited By ~ 4

Author(s):

Ashley J. Rust ◽

Samuel Saxe ◽

John McCray ◽

Charles C. Rhoades ◽

Terri S. Hogue

Keyword(s):

Water Quality ◽

Vegetation Index ◽

Field Capacity ◽

Phosphorus Loading ◽

Burn Severity ◽

Nitrogen And Phosphorus ◽

Western Us ◽

Normalised Difference Vegetation Index ◽

Green Vegetation ◽

Quality Response

Wildfires commonly increase nutrient, carbon, sediment and metal inputs to streams, yet the factors responsible for the type, magnitude and duration of water quality effects are poorly understood. Prior work by the current authors found increased nitrogen, phosphorus and cation exports were common the first 5 post-fire years from a synthesis of 159 wildfires across the western United States. In the current study, an analysis is undertaken to determine factors that best explain post-fire streamwater responses observed in those watersheds. Increased post-fire total nitrogen and phosphorus loading were proportional to the catchment extent of moderate and high burn severity. While post-fire dissolved metal concentrations were correlated with pre-fire soil organic matter. Total metal concentration increased where post-fire Normalised Difference Vegetation Index, a remote sensing indicator of live green vegetation, was low. When pre-fire soil field capacity exceeded 17%, there was a 750% median increase in total metals export to streams. Overall, the current analysis identified burn severity, post-fire vegetation cover and several soil properties as the key variables explaining extended post-fire water quality response across a broad range of conditions found in the western US.

Download Full-text

Long-Term (15 Years) Results of NPS Controls in an Agricultural Watershed upon a Receiving Lake's Water Quality

Water Science & Technology ◽

10.2166/wst.1993.0447 ◽

1993 ◽

Vol 28 (3-5) ◽

pp. 441-449 ◽

Cited By ~ 8

Author(s):

Paul J. Garrison ◽

Timothy R. Asplund

Keyword(s):

Water Quality ◽

Structural Changes ◽

Soil Phosphorus ◽

Water Clarity ◽

Management Control ◽

Agricultural Watershed ◽

Control Measures ◽

Phosphorus Loading ◽

Phosphorus Concentration ◽

White Clay

Nonpoint source controls were installed in a 1215 ha agricultural watershed in northeastern Wisconsin in the late 1970. Changes were made in handling of animal wastes and cropping practices to reduce runoff of sediment and nutrients. Modelling results predicted a reduction in phosphorus runoff of 30 percent. The water quality of White Clay Lake has worsened since the installation of NPS controls. The lake's phosphorus concentration has increased from a mean of 29 µg L−1 in the late 1970s to 44 µg L−1 in recent years. Water clarity has declined from 2.7 to 2.1 m and the mean summer chlorophyll levels have increased from 9 to 13 µg L−1 with peak values exceeding 40 µg L−1. Increased phosphorus loading is not the result of elevated precipitation but instead the failure of the control measures to sufficiently reduce P loading. Most of the effort was placed on structural changes while most of the P loading comes from cropland runoff. Further, soil phosphorus concentrations have increased because of artificial fertilizers and manure spreading. The White Clay Lake experience is discouraging since the majority of the polluters in this watershed utilized some NPS control practices, including 76 percent of the farms which installed waste management control facilities.

Download Full-text

Spatio-temporal trends in the flow and water quality: response of river Yamuna to urbanization

Environmental Monitoring and Assessment ◽

10.1007/s10661-021-08873-x ◽

2021 ◽

Vol 193 (3) ◽

Author(s):

Shweta Lokhande ◽

Vinod Tare

Keyword(s):

Water Quality ◽

Temporal Trends ◽

Spatio Temporal ◽

River Yamuna ◽

Quality Response

Download Full-text

Assessment of Trophic Responses of a Reservoir to Seasonal and Annual Variations in Monsoon

Water ◽

10.3390/w13152117 ◽

2021 ◽

Vol 13 (15) ◽

pp. 2117

Author(s):

Su-mi Kim ◽

Hyun-su Kim

Keyword(s):

Water Quality ◽

Trophic State ◽

Monsoon Season ◽

Phytoplankton Growth ◽

Phosphorus Loading ◽

Nutrient Concentrations ◽

Trophic State Index ◽

Post Monsoon ◽

Post Monsoon Season ◽

State Index

The variations in water quality parameters and trophic status of a multipurpose reservoir in response to changing intensity of monsoon rain was investigated by applying a trophic state index deviation (TSID) analysis and an empirical regression model to the data collected in two periods from 2014 to 2017. The reservoir in general maintained mesotrophic conditions, and Carlson’s trophic state index (TSIc) was affected most by TSITP. Nutrient concentrations, particularly phosphorus, did not show strong correlations with precipitation, particularly in the period with weak monsoon, and a significant increase in total phosphorus (TP) was observed in Spring 2015, indicating the possibility of internal phosphorus loading under decreased depth and stability of water body due to a lack of precipitation. TSIChl was higher than TSISD in most data in period 1 when a negligible increase in precipitation was observed in the monsoon season while a significant fraction in period 2 showed the opposite trend. Phytoplankton growth was not limited by nutrient limitation although nutrient ratios (N/P) of most samples were significantly higher than 20, indicating phosphorus-limited condition. TSID and regression analysis indicated that phytoplankton growth was limited by zooplankton grazing in the Spring, and that cell concentrations and community structure in the monsoon and post-monsoon season were controlled by the changing intensity of the monsoon, as evidenced by the positive and negative relationships between community size and cyanobacterial population with the amount of precipitation in the Summer, respectively. The possibility of contribution from internal loading and an increase in cyanobacterial population associated with weak monsoon, in addition to potential for nutrient enrichment in the post-monsoon season, implies a need for the application of more stringent water quality management in the reservoir that can handle all potential scenarios of eutrophication.

Download Full-text

Simulating Diurnal Variations of Water Temperature and Dissolved Oxygen in Shallow Minnesota Lakes

Water ◽

10.3390/w13141980 ◽

2021 ◽

Vol 13 (14) ◽

pp. 1980

Author(s):

Bushra Tasnim ◽

Jalil A. Jamily ◽

Xing Fang ◽

Yangen Zhou ◽

Joel S. Hayworth

Keyword(s):

Water Quality ◽

Dissolved Oxygen ◽

Water Temperature ◽

Shallow Lakes ◽

Quality Model ◽

Lake Water Quality ◽

Ecological Processes ◽

Turbulent Diffusion Coefficient ◽

Hourly Data ◽

Mean Square Errors

In shallow lakes, water quality is mostly affected by weather conditions and some ecological processes which vary throughout the day. To understand and model diurnal-nocturnal variations, a deterministic, one-dimensional hourly lake water quality model MINLAKE2018 was modified from daily MINLAKE2012, and applied to five shallow lakes in Minnesota to simulate water temperature and dissolved oxygen (DO) over multiple years. A maximum diurnal water temperature variation of 11.40 °C and DO variation of 5.63 mg/L were simulated. The root-mean-square errors (RMSEs) of simulated hourly surface temperatures in five lakes range from 1.19 to 1.95 °C when compared with hourly data over 4–8 years. The RMSEs of temperature and DO simulations from MINLAKE2018 decreased by 17.3% and 18.2%, respectively, and Nash-Sutcliffe efficiency increased by 10.3% and 66.7%, respectively; indicating the hourly model performs better in comparison to daily MINLAKE2012. The hourly model uses variable hourly wind speeds to determine the turbulent diffusion coefficient in the epilimnion and produces more hours of temperature and DO stratification including stratification that lasted several hours on some of the days. The hourly model includes direct solar radiation heating to the bottom sediment that decreases magnitude of heat flux from or to the sediment.

Download Full-text

Constructed wetlands as an alternative restoration measure for shallow lakes

Water Science & Technology ◽

10.2166/wst.2013.412 ◽

2013 ◽

Vol 68 (7) ◽

pp. 1672-1678 ◽

Cited By ~ 4

Author(s):

M. Bozic ◽

G. Nikolic ◽

Z. Rudic ◽

V. Raicevic ◽

B. Lalevic

Keyword(s):

Water Quality ◽

Constructed Wetland ◽

Shallow Lakes ◽

Treatment Plant ◽

Technical Solution ◽

Lake Water Quality ◽

Cultural Eutrophication ◽

Quality Of Water ◽

Restoration Measure ◽

Key Aspects

This paper deals with the consequences of cultural eutrophication and unconventional solutions for shallow lake restoration. Cultural eutrophication is the primary problem that affects especially shallow lakes, due to their physical characteristics (e.g. shallow depth, lack of stratification). Palic Lake, a very shallow Pannonian lake, received treated municipal wastewaters coming from the lagoons of a wastewater treatment plant. The sewage discharge mainly increased the nutrient load to the lake in the last decades. The lake sustainability is affected by inappropriate quality of water that flows into the lake, and abundance of deposited sediment. The technology that can provide both improvement of water quality and resolution of the sediment problem is a constructed wetland, which is designed to utilise the natural processes involving wetland vegetation, soil and their associated microbial assemblages to assist in additional water treatment. The technical solution is based on three key aspects: quality and quantity of deposited sediment, enriched by nutrients; effluent quality; desired lake water quality. A designed constructed wetland can accomplish the desired water quality and gradually remediate deposited sediment.

Download Full-text