Evolution and changes in the morphologies of Sudanese cities
Architecture ; Cultural heritage ; Settlement ; Sixth Century ; Sudan ; Twenty-first century ; Urban area ; Urban change ; Urban fringe ; Urban morphology ; Urban planning ; Urbanization
This article investigates the morphological evolution of Sudanese and involves consideration of town planning, building form, and the pattern of land and building utilization.It identifies three broad morphologies: indigenous, African-Islamic
, and European style (colonial). The ongoing, rapid urbanization of African cities in general and Sudanese cities in particular points to a need to understand the structure of this urbanization. The morphology of cities includes not only physical structure
, but the cultural heritage, economic, and historical values on which it is based. Therefore, preservation, redevelopment, and urban policy underlying future urban expansion must be based on the nature of cities’ morphologies and development.
Evaluating proxies for estimating subaerial beach volume change across increasing time scales and various morphologies
This study assesses the impacts of morphologic variations, associated with beach cusps and nourishment material, on volume change estimates from profiles and shoreline change at 0.5 to 3.5 year time periods. Volume changes at the edges
of nourishment areas are not captured well by profiles. When the nourishment material is graded to a ramped morphology, which minimizes across-beach morphologic variability, the shoreline-change proxy does accurately estimate volume changes. Both proxies estimate
volume changes inaccurately at beaches where volume changes oscillate between erosion and accretion on both short and long time scales because the magnitude of small-scale changes in volume from the formation and erosion of morphologic features
Morphology-dependent water budgets and nutrient fluxes in Arctic thaw ponds
Permafrost on the Arctic Coastal Plain of Alaska creates unique pond morphologies : deep troughs, shallow low-centred polygons (LCPs) and larger coalescent ponds. By monitoring seasonal trends in pond volume and chemistry, the AA. evaluated whether
pond morphology and size affect water temperature and desiccation, and nitrogen (N) and phosphorus (P) fluxes. Evaporation was the largest early-summer water flux in all pond types. LCPs dried quickly and displayed high early-summer nutrient
accelerate mid-summer desiccation. Given their morphology, troughs may remain wet, become warmer and derive greater nutrient loads from their thawing banks. Overall, seasonal- to decadal-scale warming may increase ecosystem productivity in troughs relative
Morphological patterns of headwater streams based in flysch bedrock : Examples from the Outer Western Carpathians
The AA .evaluated a large dataset of channel-reaches coming out from flysch midmountains. Two new channel-reach morphologies were distinguished with respect to their differences in the ratio of sediment supply to transport capacity : bedrock
-cascades and step-rapids. The chaining of channel-reach morphologies by gradient criteria and the parameters of channel gradient and bankfull width related to the basin area show similar trends, when compared to other recent studies. By contrast, bankfull
depth indicates its independence on increasing basin area. Significant downstream coarsening of bed material occurs only in alluvial stepped-bed morphologies (cascades, step-pools and step-rapids) mainly due to strong slope–channel coupling processes
Assessment of the planimetric morphology of barchan dunes
In this study, high resolution images are combined with field measurements in order to quantitatively study the migration and long term changes in the shape and morphology of barchans. The results indicated a power correlation between height
. The minimum and the maximum annual displacements of the barchans were 9 and 22 m, respectively, in the study area. It was also demonstrated that the best morphologic estimators for migration rate of dunes are in this order : width, mean curvature of windward
Morphological responses and sediment processes following a typhoon-induced dam failure, Dahan River, Taiwan
and spatial patterns in morphology and likely sediment transport regimes. Results document the rapid response of the reservoir and downstream channel, which occurred primarily through incision and adjustment of channel gradient. Hydraulic simulations
, valley configuration, and distance from the dam is needed to explain the rate and pattern of morphological changes across study periods.
Morphological records of storm floods exemplified by the impact of the 1872 Baltic storm on a sandy spit system in south-eastern Denmark
This study investigates the morphological impacts of the 1872 Baltic storm flood on a beach-ridge system (sandy spit) in south-eastern Denmark and evaluates the frequency of extreme storm flood events in the area over a longer time perspective
. This paper combines field studies of morphology and sedimentary deposits, studies of historical maps, digital terrain model, ground-penetrating radar profiles, and luminescence dating. Four phases were highlighted. The studied beach-ridge system records about
Spatial patterns and morphology of termite (Macrotermes falciger) mounds in the Upper Katanga, D.R. Congo
This study examines the spatial distribution patterns and morphological characteristics of Macrotermes falciger mounds in the peri-urban zone of Lubumbashi, D.R. Congo. Spatial patterns of mounds were assessed using high-resolution satellite images
for 24 plots of variable size (3 to 27 ha). Soil morphological features were described for five termite-mound profiles of 5 to 9 m depth/height. The high relative number of inactive mounds in the region, with regular distribution patterns, suggests
the recognition of individual logs. Results show that wood tends to disperse in generally small accumulations, with higher spatial density on top of sediment bars, and is frequently remobilized due to the intense morphological changes. The amount of wood stored
and largely resembling the turnover rate of exposed bars. For the simulated conditions, significant effects of wood on bed morphology were not observed, suggesting that interactions with fine sediments and living vegetation are crucial to form large, stable
wood jams able to bring about relevant morphological changes.
The impact of beaver dams on the morphology of a river in the eastern United States with implications for river restoration
A channel on the Atlantic Coastal Plain was analyzed before, during, and after beaver dams were constructed to evaluate the lasting impact of the beaver on channel morphology. The channel was actively evolving in a former reservoir area upstream
The aim of this study is to evaluate the effect of rill morphology on roughness and hence to assess the Manning–Strickler roughness coefficient (kSt) by rill morphological data. A laboratory experiment was set up to analyse rill hydraulics
and roughness of I.) Free Developed Rill (FDR) flows and II.) Straight Constrained Rill (SCR) flows in the flume. It is highlighted that rill roughness was highly variable and relates to rill morphology. The AA. conclude that flow path tortuosity can be used
Time-focused investigation of river channel morphological changes due to extreme floods
and 2009) in the GIS environment on the example of the 13.2 km long less regulated and laterally partly-confined meandering reach of the Ondava River (Eastern Slovakia). The photographs were chosen in a way to capture the morphological changes that occurred
Alluvial reaches in the source region of the Yangtze River exhibit predominantly braided channel planforms, while equivalent reaches in the source region of the Yellow River have more diverse planform morphologies including anastomosing/braided
planforms. A short period above freezing, coincident with recurrent yet pulsed flows in the source region of the Yangtze River, suppress riparian vegetation growth, promoting the development of braided channel morphologies. In contrast, a milder climate
, coincident with less variable flows in the source region of the Yellow River, permit the establishment of different forms of riparian vegetation, thereby supporting the development of a wider range of channel planform morphologies.
Magnetic tracing of fine-sediment over pool-riffle morphology
This paper describes the methodology behind the artificial magnetic enhancement of iron-stained sand, and presents the results from sand tracing exercises conducted on two gravel-bed channels with pool-riffle morphology; one unregulated and sinuous
This article indicates the quantitative tools, with assistance of which it is possible to characterize the morphology (shape) of the valley network and determine their variability caused by the scale change. The monitored morphometric
and statistical analyses agreed with wave model results. These were correlated to morphological change and it was concluded that offshore islands change wave dynamics and modify the morphology of embayed beaches in their lee. Consequently, this work provides