JKUAT COHRED CONFERENCE Series
http://localhost/xmlui/handle/123456789/2199
2024-03-28T23:18:27ZA Model for Stability Analysis of a Multi-Layered River Bank (SAMLR)
http://localhost/xmlui/handle/123456789/4147
A Model for Stability Analysis of a Multi-Layered River Bank (SAMLR)
Amiri-Tokaldany, E.; Darby, S. E.
River bank erosion can result in considerable riparian land loss and the delivery of
large volumes of sediment to reaches downstream. Consequently, the ability to predict the
stability and failure geometry of eroding river banks is an important prerequisite for estimating
the rate of bank erosion and sediment yield associated with bank erosion. In this
paper a new model capable of analyzing the stability of layered river banks is introduced.
The new model takes into consideration the effects of positive pore water pressure in the
saturated portion, and negative pore water pressure in the unsaturated portion, of the
bank. Also, the role of hydrostatic confining pressure due to the water level in the river
and the effects of the water in tension crack on stability analysis is accounted for. Unlike
many previous analyses, the failure plane is not constrained to pass through the toe of the
bank. However, it considers only planar-type failure mechanism. Finally the bank profile
geometry is not restricted to a special case. The new model has been tested using field data
sets from a site on the Sieve River in Italy and a site on Goodwin Creek in Mississippi.
The results show some agreement between the predicted and observed values of bank stability.
paper
2018-02-15T00:00:00ZFish Parasites in Zarivar Lake
http://localhost/xmlui/handle/123456789/4145
Fish Parasites in Zarivar Lake
Jalali1, B.; Barzegar, M.
Twenty four ecto- and endo- parasite species were found in different organs of eight native
and exotic fish species in Zarivar Lake situated in the far west of Iran. Overall, 1000
fish specimens belonging to the Dactylogyridae, Gyrodactylidae families the Cyprinidae,
Poeciliidae and Mastacembelidae families were examined during 2001 and 2002. Of them,
five Protozoans, including Trichodina pediculus, Trichodina sp and Myxobolus molnari, a
pansporogenic stage of the Myxosporean plasmodia and Ichthyophthirius multifiliis were
recorded. Of the Metazoan parasites, 12 monogenean species, mostly belonging to the
Dactylogyridae, Gyrodactylidae families and the Ancyrocephalinae subfamily, were found
and identified at species and genus level. The number of helminthes reached 15 by adding
one Digenea metacercaria (Diplostomum spathaceum) and 2 coelozoic Cestoda species.
Crustacean species found on both of native and exotic fishes, belonging to Copepoda and
Branchiora orders comprised of Argulus foliaceus and Lernaea cyprinacea, in addition an
unknown Argulus was also found on skin and gills of spiny eel which identified to genus
level. The only nematode found in the intestine of common carp was identified as Pseudocapillaria
tomentosa. Besides the first record of parasites of spiny eel, the seasonal prevalence
of ligulosis is presented. Additionally, zoogeographical analysis and species composition
of parasitic fauna of Zarivar Lake are discussed.
paper
2018-02-15T00:00:00ZPrediction of Irrigation Water Salinity by Means of Hydrometry
http://localhost/xmlui/handle/123456789/4120
Prediction of Irrigation Water Salinity by Means of Hydrometry
Khorsandi, F.; Yazdi, F. Alaei
Salinity is the primary water quality concern in irrigated agriculture. An Electrical
Conductivity (EC) meter and a hydrometer are two possible methods for measurement of
irrigation water salinity. The conductivity meter method is based on measuring the
amount of electrical current that a fluid will support. Although it is the most widely used
method, the instrumentation is rather expensive and in some instances may require
sample dilution. The hydrometer method is based on measuring the density of the fluid.
The main objectives of this study were to compare these two methods and, based on
hydrometer method, develop empirical models for prediction of EC, sodium adsorption
ratio (SAR), and the principle ion concentrations in the irrigation waters of Yazd
Province, Iran. The electrical conductivity, temperature, and density of 206 water samples
from wells across Yazd Province were measured. Temperature correction factors for
adjusting the hydrometer reading to 25 oC were determined. The correlation between EC
and hydrometer readings was high (R2 = 0.97). Although the empirical model developed
for prediction of EC slightly underpredicted the measured values, it is still accurate
enough for practical purposes. Hydrometer readings were also highly correlated with the
principle ions and SAR. The salt type also affected the hydrometer readings. Magnesium
sulfate solution had the highest density among the major salt types present in irrigation
waters. Finally, a chart was developed for rough estimations of EC, sodium and chlorine
concentrations in irrigation waters of Yazd Province, Iran.
paper
2018-02-14T00:00:00ZThe Agha Jari Formation: A Potential Source of Ammonium and Nitrate Nitrogen Fertilizers
http://localhost/xmlui/handle/123456789/4116
The Agha Jari Formation: A Potential Source of Ammonium and Nitrate Nitrogen Fertilizers
Yazdian, A. R.; Kowsar, S. A.
Nitrogen deficiency ranks right behind water shortage as the second-most constraint to
crop production in the coarse-loamy sand of the Gareh Bygone Plain (GBP) in southern
Iran. Since better resource utilization is essential for wise energy management, contrary
to reported cases, surface water pollution by N maybe a boon in the GBP. The Agha Jari
Formation (AJF), in which the Bisheh Zard Basin (BZB) has been formed, contains anomalously
high concentrations of NO3
− and NH4
+ in its calcareous sandstone, siltstone
and marl components. As about 60% of our irrigation water is supplied through underground
resources and are heavily over-exploited, the artificial recharge of groundwater
(ARG) is actively pursued in Iran. Therefore, a major proportion of the ephemeral discharge
of the BZB is spread over 1365 hectares of sedimentation basins and recharge
ponds of the ARG system in the GBP. These basins and ponds are covered with improved
rangeland, and eucalyptus (Eucalyptus spp.) and acacia (Acacia spp.) plantations. Therefore,
it is expected that some of the geological-N dissolved in floodwater, and also carried
by the suspended load, will reach the groundwater and supply the plants coming in contact
with the water and/or sediment. Moreover, as both NO3
− and NH4
+ are considered
pollutants of groundwater, the relative abundance of each should be determined, so that
possible remedial measures can be designed and implemented. To study the origin of N
in the BZB, and to investigate the fate of the dissolved and adsorbed N as it travels from
the watershed to the root zone, 13 rock samples, 5 floodwater samples and 81 soil samples
were collected and analyzed for NO3
−and NH4
+. The NO3
−-N concentration was lower than
that of NH4
+-N in most of the samples: 5.1 vs. 9.6 mg kg-1 in rocks, 13.4 vs.17.4 mg L-1 dissolved
in floodwater, 1.3 vs.4.3 mg kg-1 carried by the suspended load, and 10.6 vs.15.5 mg
kg-1 in the 0-125 cm soil profile. Assuming that the mean annual inflow of the GBP-ARG
system is 7 million m3 ,we receive 89.4±52.4 kg ha-1 yr-1 of NH4
+-N and 68.7± 24.6 kg ha-
1 yr-1 of NO3
−-N, of which some furnishes the vegetative cover with N. A part of what
remains may reach the watertable after passing through the vadose zone.
2018-02-14T00:00:00Z