Influence of antecedent hydrologic conditions on patterns of hydrochemical export from a first-order agricultural watershed in Southern Ontario, Canada

2010 ◽  
Vol 389 (1-2) ◽  
pp. 101-110 ◽  
Author(s):  
M.L. Macrae ◽  
M.C. English ◽  
S.L. Schiff ◽  
M. Stone
Keyword(s):  
Agricultural Watershed ◽  
Southern Ontario ◽  
First Order ◽  
Hydrologic Conditions

scholarly journals Spatial-Temporal Dynamics of Runoff Generation Areas in a Small Agricultural Watershed in Southern Ontario

2015 ◽  
Vol 07 (01) ◽  
pp. 14-40 ◽  
Author(s):  
Kamran Chapi ◽  
Ramesh P. Rudra ◽  
Syed I. Ahmed ◽  
Alamgir A. Khan ◽  
Bahram Gharabaghi ◽  
...  
Keyword(s):  
Temporal Dynamics ◽  
Agricultural Watershed ◽  
Runoff Generation ◽  
Southern Ontario

Dissipation of Permethrin in Limnocorrals

1985 ◽  
Vol 42 (1) ◽  
pp. 70-76 ◽  
Author(s):  
K. R. Solomon ◽  
J. Y. Yoo ◽  
D. Lean ◽  
N. K. Kaushik ◽  
K. E. Day ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Water Chemistry ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Secchi Disk ◽  
Secchi Disk Depth ◽  
Southern Ontario ◽  
First Order ◽  
First Order Kinetics ◽  
Rate Of Dissipation

Permethrin (3-phenoxybenzyl(1RS)-cis,trans-3-(2,2-dimethy[-3-dichlorovinyl)-2,2-dimethylcyciopropanecarboxylate) applied to approximately 100-m3 enclosures (limnocorrals) in a small mesotrophic lake in Southern Ontario (47°51′25″N; 77°25′30″W) at concentrations of 500, 50, 5, and 0.5 μ∙L−1 dissipated from the water rapidly and approximated first-order kinetics in the first 8–12 d. Time taken for 50 and 90% dissipation ranged from 1.65 and 3.65 d, respectively, at 0.5 μ∙L−1 to 3.5 and 6.75 d, respectively, at 50 μ∙L−1. Inter- and intra-seasonal replication of dissipation patterns was good. Rate of dissipation varied slightly with depth, normally being slower at greater depth. Absorption of permethrin to sediments was rapid, penetration shallow, and disappearance slow. Permethrin had no effect on water chemistry but there was an increase in the Secchi disk depth in the treated limnocorrals. Dissolved inorganic carbon decreased in all limnocorrals, including controls after treatment, suggesting precipitation of calcium carbonate which may act as a scavenging agent for permethrin in the water. Limnocorrals are a useful tool for evaluating the behavior of pesticides in the aquatic system.

ASSESSMENT AND UNCERTAINTY ANALYSIS OF EUTROPHICATION FOR TE-CHI RESERVOIR, TAIWAN

1994 ◽  
Vol 30 (2) ◽  
pp. 73-80 ◽  
Author(s):  
Yu-Ming Wang ◽  
Ming-Chun Wu ◽  
Jan-Tai Kuo
Keyword(s):  
Uncertainty Analysis ◽  
Total Phosphorus ◽  
Trophic State ◽  
Load Resistance ◽  
Phosphorus Concentration ◽  
Total Phosphorus Concentration ◽  
Order Analysis ◽  
First Order ◽  
The Future ◽  
Hydrologic Conditions

This paper describes the development and application of uncertainty analysis to evaluate the risk of eutrophication for Te-Chi Reservoir, Taiwan. Two methods, probabilistic model and first-order analysis of uncertainty (FOAU), were used to quantify the expected variability of the total phosphorus concentration in the reservoir. Based on the load-resistance analysis, these two methods were applied and compared to calculate the risk of eutrophication for Te-Chi Reservoir. An approach is also proposed herein to evaluate the trophic state in the future. Since the trophic state for Te-Chi Reservoir is strongly dependent on hydrologic conditions, incorporating an annual ARM A inflow model with the empirical total phosphorus model developed in previous work, the trophic state in the future was investigated. The significant advantage of the proposed approach is that it provides a simplified and useful procedure to evaluate the risk of eutrophication for the reservoir in the future.

scholarly journals Development of GIS Interface Tool for GAMES Model and Its Application to an Agricultural Watershed in Southern Ontario

2018 ◽  
Vol 08 (03) ◽  
pp. 312-325 ◽  
Author(s):  
Kishor Panjabi ◽  
Nabil Allataifeh ◽  
Chen Dai ◽  
Ramesh Rudra ◽  
Pradeep Goel ◽  
...  
Keyword(s):  
Agricultural Watershed ◽  
Southern Ontario ◽  
Gis Interface

scholarly journals Impact of a First-Order Riparian Zone on Nitrogen Removal and Export from an Agricultural Ecosystem

2001 ◽  
Vol 1 ◽  
pp. 642-651 ◽  
Author(s):  
J.T. Angier ◽  
G.W. McCarty ◽  
T.J. Gish ◽  
C.S.T. Daughtry
Keyword(s):  
Preferential Flow ◽  
Riparian Zone ◽  
Stream Water ◽  
Agricultural Watershed ◽  
Agricultural Ecosystem ◽  
First Order ◽  
Nitrate N ◽  
N Removal ◽  
Order Of Magnitude ◽  
Groundwater Nitrogen

Riparian zones are reputed to be effective at preventing export of agricultural groundwater nitrogen (N) from local ecosystems. This is one impetus behind riparian zone regulations and initiatives. However, riparian zone function can vary under different conditions, with varying impacts on the regional (and ultimately global) environment. Rates of groundwater delivery to the surface appear to have significant effects on the N-removing capabilities of a riparian zone. Research conducted at a first-order agricultural watershed with a well-defined riparian zone in the Maryland coastal plain indicates that more than 2.5 kg/day of nitrate-N can be exported under moderate-to-high stream baseflow conditions. The total nitrate-N load that exits the system increases with increasing flow not simply because of the greater volume of water export. Stream water nitrate-N concentrations also increase by more than an order of magnitude as flow increases, at least during baseflow. This appears to be largely the result of changes in dominant groundwater delivery mechanisms. Higher rates of groundwater exfiltration lessen the contact time between nitrate-carrying groundwater and potentially reducing riparian soils. Subsurface preferential flow paths, in the wetland and adjacent field, also strongly influence N removal. Simple assumptions regarding riparian zone function may be inadequate because of complexities observed in response to changing hydrologic conditions.

STATISTICAL STRUCTURE OF AEROMAGNETIC FIELD

Geophysics ◽  
1970 ◽  
Vol 35 (2) ◽  
pp. 279-292 ◽  
Author(s):  
Prabhakar S. Naidu
Keyword(s):  
Order Statistics ◽  
Probability Distribution Function ◽  
Point Of View ◽  
Statistical Structure ◽  
Southern Ontario ◽  
Second Order Statistics ◽  
First Order ◽  
Non Gaussian ◽  
The Right ◽  
Mean Variance

A study of the statistical structure of an aeromagnetic field over approximately four and a half thousand square miles of the Parry Sound and Huntsville area of southern Ontario has revealed the following: From the point of first‐order statistics, that is, mean, variance, skewness, and probability distribution function, the right half of the area which is occupied by hornblende or biotite migmatite is homogeneous and Gaussian, whereas the left half, which is mainly occupied by amphibolite gneiss, is generally inhomogeneous and non‐Gaussian. From the point of view of second‐order statistics, that is, the spectrum, the entire field appears to be inhomogeneous. This difference between statistical pictures is attributed to the fact that there are at least two preferred directions of strike, which influence the shape of the spectrum significantly.

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