Factors limiting fish populations in the Loch Fleet system, an acidic drainage system in south-west Scotland

1988 ◽  
Vol 32 (1) ◽  
pp. 101-118 ◽  
Author(s):  
A. W. H. Turnpenny ◽  
C. H. Dempsey ◽  
M. H. Davis ◽  
J. M. Fleming
1988 ◽  
Vol 34 (118) ◽  
pp. 327-332 ◽  
Author(s):  
Peter G. Johnson ◽  
Diane Lacasse

Abstract Glaciated valleys of the Dalton Range in the south-west Yukon Territory are dominated by rock glaciers identified as glacier ice-cored debris systems. The two rock glaciers studied have different amounts of deformation at present, resulting from post-formation mechanics. The primary formation of lobes of the rock glaciers resulted from periods of glacier activity in the Neoglacial, although older lobes, probably late Pleistocene in age, occur below the Neoglacial lobes. The hydrological systems of the rock glaciers have played a major role in the post-formation deformation of the land forms and the present drainage system is entirely sub-surface. The explanation for the extensive occurrence of rock glaciers in the Dalton Range is lithological as a result of the high susceptibility of the Upper Jurassic/Lower Cretaceous sediments to frost action and glacier erosion.


Rural History ◽  
2008 ◽  
Vol 19 (1) ◽  
pp. 1-27 ◽  
Author(s):  
ANDREW GRITT

AbstractThis article investigates the changing administrative context of drainage in south-west Lancashire from the mid-seventeenth to the mid-nineteenth centuries. Successive schemes managed by Commissions of Sewers, piecemeal reclamation and private agreement were characterised by primitive technology, under-investment and poor management. Consequently, their achievements were limited. Large scale drainage schemes under the control of single individuals or powerful syndicates enjoyed greater success, but to coordinate drainage across an ecosystem that went beyond estate boundaries required state intervention in the form of an Act of Parliament of 1779. After some initial success the drainage commissioners found themselves immersed in legal wranglings with landowners and maintenance of the drainage system largely fell into abeyance. It was not until the landlords provided the administrative and financial resources to invest in technological solutions in the 1840s that the land achieved its full potential. It is argued that drainage of this land, resulting in its transformation from some of the worst land in the country to some of the best, was a major contributor not only to the agricultural success of the region, but also to Lancashire's industrial success.


1988 ◽  
Vol 34 (118) ◽  
pp. 327-332
Author(s):  
Peter G. Johnson ◽  
Diane Lacasse

AbstractGlaciated valleys of the Dalton Range in the south-west Yukon Territory are dominated by rock glaciers identified as glacier ice-cored debris systems. The two rock glaciers studied have different amounts of deformation at present, resulting from post-formation mechanics.The primary formation of lobes of the rock glaciers resulted from periods of glacier activity in the Neoglacial, although older lobes, probably late Pleistocene in age, occur below the Neoglacial lobes. The hydrological systems of the rock glaciers have played a major role in the post-formation deformation of the land forms and the present drainage system is entirely sub-surface. The explanation for the extensive occurrence of rock glaciers in the Dalton Range is lithological as a result of the high susceptibility of the Upper Jurassic/Lower Cretaceous sediments to frost action and glacier erosion.


2021 ◽  
Author(s):  
MEHRAJ U DIN DAR ◽  
J.P. Singh

Abstract In the present study, DRAINMOD-NII model was calibrated for the years 2018-2019 and validated for the period 2019-2020 over the two cropping years. The model simulations were statistically evaluated by comparing the measured drain flows and nitrate-nitrogen (NO3-N) with the model simulated drain outflows and nitrate loss. The study results depicted closer agreement between the simulated and observed results for both the calibration and validation periods. The Root Mean Square Error (RMSE) of the drainage rate was 8.88 cm more than observed data,15.41, 0.53 and 0.57 cm were the values recorded for PBIAS, modelling efficiency (NSE) and R2. The similar parameter values for nitrogen load were recorded to be 0.14, 2.76 ,0.84 and 0.88 respectively during the calibration period for rice wheat system. The model was statistically tested during the validation period also, confirming DRAINMOD-NII has the capability to simulate nitrogen losses from the area subjected to subsurface drainage system.


Author(s):  
Yakubu Mohammed ◽  
Ashe Kalli Gazali ◽  
John Onu Odihi ◽  
Mohammed Mala Daura

The aim of present study is to spatially analyze the topographic lineaments of tectonic origin in the Miringa Volcanic Zone located in the northwestern part of the Biu Plateau. To achieve such aim, SRTM of spatial resolution 12.5 m was utilized. The lineaments were automatically extracted by using PCI GEOMARTICA software version 10. This was followed by field work for ground thruting and to establish field relationships. ArcGis 10.5 software version was used for spatial analysis of lineaments while Rockworks version 16 was used in creating the Rossace used in lineament trend analysis and other related statistical variables associated with the lineaments of the study area. 2036 linear structures were identified in the area with a total length of 30,193.85 m. The maximum length of lineament recorded in the study area is 150 m while the minimum is 3.68 m. Field work revealed that most of the lineaments in the area developed from the weathering of contacts between successive volcanic beds in areas overlaid by the highly dissected plateaus, escarpment slopes and denudation hills. Trend analysis of lineaments of the study area indicates that the direction of lineaments tend to lie in the North-east to southwest direction (Azimuth 45°-225°) which has same direction with major drainage system and most of the volcanoes of the area. This signifies the presence of a major fissure trending in the north-east to south-west direction as the primary tectonic structure of the area. Subsequent exogenic processes exploited this structure leading to the formation of other micro-lineaments that trend along the same direction.


1987 ◽  
Vol 32 (1-2) ◽  
Author(s):  
R. Harriman ◽  
B.R.S. Morrison ◽  
L.A. Caines ◽  
P. Collen ◽  
A.W. Watt

Author(s):  
E. M. B. Sorensen ◽  
R. R. Mitchell ◽  
L. L. Graham

Endemic freshwater teleosts were collected from a portion of the Navosota River drainage system which had been inadvertently contaminated with arsenic wastes from a firm manufacturing arsenical pesticides and herbicides. At the time of collection these fish were exposed to a concentration of 13.6 ppm arsenic in the water; levels ranged from 1.0 to 20.0 ppm during the four-month period prior. Scale annuli counts and prior water analyses indicated that these fish had been exposed for a lifetime. Neutron activation data showed that Lepomis cyanellus (green sunfish) had accumulated from 6.1 to 64.2 ppm arsenic in the liver, which is the major detoxification organ in arsenic poisoning. Examination of livers for ultrastructural changes revealed the presence of electron dense bodies and large numbers of autophagic vacuoles (AV) and necrotic bodies (NB) (1), as previously observed in this same species following laboratory exposures to sodium arsenate (2). In addition, abnormal lysosomes (AL), necrotic areas (NA), proliferated rough endoplasmic reticulum (RER), and fibrous bodies (FB) were observed. In order to assess whether the extent of these cellular changes was related to the concentration of arsenic in the liver, stereological measurements of the volume and surface densities of changes were compared with levels of arsenic in the livers of fish from both Municipal Lake and an area known to contain no detectable level of arsenic.


2019 ◽  
Vol 25 ◽  
pp. 317
Author(s):  
Ayotunde Ale ◽  
Opeyemi Aloro ◽  
Ayanbola Adepoju
Keyword(s):  

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