Estimating low flows for Coastal Plain watersheds

2013 ◽  
Author(s):  
J. M. Sheridan ◽  
R.G. Williams and D.D. Bosch
Keyword(s):  
10.1029/ft172 ◽  
1989 ◽  
Author(s):  
W. Burleigh Harris ◽  
Vernon J. Hurst ◽  
Paul G. Nystrom ◽  
Lauck W. Ward ◽  
Charles W. Hoffman ◽  
...  

Author(s):  
Ondrej Ledvinka ◽  
◽  
Pavel Coufal ◽  

The territory of Czechia currently suffers from a long-lasting drought period which has been a subject of many studies, including the hydrological ones. Previous works indicated that the basin of the Morava River, a left-hand tributary of the Danube, is very prone to the occurrence of dry spells. It also applies to the development of various hydrological time series that often show decreases in the amount of available water. The purpose of this contribution is to extend the results of studies performed earlier and, using the most updated daily time series of discharge, to look at the situation of the so-called streamflow drought within the basin. 46 water-gauging stations representing the rivers of diverse catchment size were selected where no or a very weak anthropogenic influences are expected and the stability and sensitivity of profiles allow for the proper measurement of low flows. The selected series had to cover the most current period 1981-2018 but they could be much longer, which was considered beneficial for the next determination of the development direction. Various series of drought indices were derived from the original discharge series. Specifically, 7-, 15- and 30-day low flows together with deficit volumes and their durations were tested for trends using the modifications of the Mann– Kendall test that account for short-term and long-term persistence. In order to better reflect the drivers of streamflow drought, the indices were considered for summer and winter seasons separately as well. The places with the situation critical to the future water resources management were highlighted where substantial changes in river regime occur probably due to climate factors. Finally, the current drought episode that started in 2014 was put into a wider context, making use of the information obtained by the analyses.


2000 ◽  
Vol 30 (3) ◽  
pp. 474-476 ◽  
Author(s):  
LUIZ JOSÉ TOMAZELLI ◽  
SÉRGIO REBELLO DILLENBURG ◽  
JORGE ALBERTO VILLWOCK

2006 ◽  
pp. 3-87 ◽  
Author(s):  
N. V. Matveyeva

Bolshevik Isl. is the one of the largest islands within the Severnaya Zemlya archipelago. It is situated in the southern part of the polar desert zone. In the course of three field work trips in 1997, 1998 and 2000 years 252 relevees were made in its southern part on three geomorphologic surfaces: coastal plain, inner upland close to glacier and ancient high river terraces. As the result 27 syntaxonomical units of different rank (15 associations, 2 subassociations, 2 variants, and 8 community types) were described using Braun-Blanquet approach. All syntaxa, except one, are new and mostly similar to communities described on Franz Josef Land. The problems were to put new syntaxa into the higher level units (including class) within the syntaxonomical hierarchy. The main bulk of syntaxa, both zonal and intrazonal ones, has to be preliminary placed into Salicetea herbaceae class although there is a lot of reasons to consider zonal syntaxa as a new class that is specific for the polar desert zone. In any case, there are no one syntaxon that can be referred to Loiseleurio-Vaccinietea class that combines zonal vegetation in the tundra zone. The wide ecological range of great majority of species as well as the changes of their intralandscape distribution compare to the tundra zone made additional difficulties in finding character and differential species. 340 species (vascular plants — 52, mosses — 97, liverworts — 41, lichens — 150), that compiles 73 % of the whole island flora and 84 % of its southern part, were recorded within the all relevees. Almost half of these (182) are very rare on the island and 127 species were met 1—2 times. There are 70 species with wide ecological range throughout all landscape types with such commonly distributed herbs as Saxifraga cernua, S. hyperborea and Stellaria ed­ward­sii, mosses Polytrichastrum alpinum and Sanionia uncinata and lichen Stereocaulon rivulorum among these. Phippsia algida, the character species for snow bed communities, occurs in about 70 % of syntaxa. Useful for differentiation of syntaxa have been appeared 87 species. Few species with wide distribution within a landscape demonstrate their preference to a certain syntaxon by higher abundance (preferential character species). These are mostly bryophytes: mosses Bryum cryophilum and Grimmia torquata, and liver­worts Gymnomitrion corallioides, Marsupella arctica and Scapania crassiretis. Cryptogam species predo­minate in the whole flora as well as in each syntaxon. The number of species varies from 12 to 70 per sample plots 5÷5 m and from 20 to 195 in different syntaxa. The richest in species (70 per community and about 190 for association) are zonal plant communities on the accumulative coastal plain in the region of Sol­nechnaya Bay, the poorest one, with 10 and 20 species consequently, is ass. Hygrohypno polari—Saxifragetosum hyperboreae that was described on the upland, close to glacier in the inner part of island.


Sign in / Sign up

Export Citation Format

Share Document