Flat Alluvial Plain Research Articles

A Botanical Tour to Subansiri Frontier Division (NEFA)

A botanical collection tour along the 100 Km. road track passing through, the Dafla hills and Apatanang valley and lying between Kimin (213 m.) and Ziro (1525 m) in the Subansiri F.D., undertaken during September 1959 yielded 383 species of angiosperms and 66 species of Pteridophytes amongst others. This paper presents the topography, climate and vegetation together with a comprehensive analysis of the floristic composition of the vegetational types and is followed by enumeration of the species in the appendix.Vegetation in the Dafla hills area visited is ascribed to tropical evergreen forest from Kimin to Pitepool and to subtropical evergreen forest, and grassland formation between Kherbari and Hapoli, the last one representing a biotic climax.Apatanang valley is a flat alluvial plain of about 20 sq. miles representing the bed of dried up lake and is very suitable for rice and millet cultivation. Pinus wallichiana and Dendrocalamus sikkimensis are extensively planted in the surrounding hillocks.The analysis of the distribution data shows the occurrence of a large number of species in the area as common to neighbouring. region e.g. Assam sharing 260 species; Sikkim, 119 species; Western Himalayas, 107 species; Burma, 51 species; Manipur, 15 species; Bengal, 29 species; Bihar and Orissa, 13 species and Deccan Peninsula, 28 species.Borreria ocymoides, Torenia asiatica and Cyanotis papilionacea, so far reported as restricted to Deccan Peninsula, Impatiens porrecta, I. paludosa and Solanum khasianum, as enemic to Khasia hills, Argyreia wallichii as endemic to Sikkim, Exacum tetragonum var. stylosa and Dendrobium chrysotoxum reported by Hooker from Burma have now been collected from Subansiri F.D.

Assessing current and future soil erosion under changing land use based on InVEST and FLUS models in the Yihe River Basin, North China

The Yihe River Basin is a key area for water conservation and soil erosion control in northern China. The excessive development of land resources is a major factor causing soil erosion and ecological degradation. However, the impacts of land use change on soil erosion in the basin are not yet clearly. Understanding the complex relationship between land use and soil erosion is an important way to promote the development of land resources utilization and ecological construction from cognition to decision-making. This study simulated the temporal-spatial changes of soil erosion in the basin from 1956 to 2020 using Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model, and evaluated the changes of soil erosion under different land use scenarios from 2020 to 2050 using Future Land Use Simulation (FLUS) model. From 1956 to 2020, the overall soil erosion intensity showed a slight decreasing trend, and the average annual soil erosion modulus was 38.21 t/ha/year. Soil erosion intensity was higher in the central and northern mountainous areas, while it was lower in the flat alluvial plains in the south. Arable land (4.07 t/ha/year) was the largest contributor to the amount of soil erosion, and land use changes caused the soil erosion intensity to fluctuate and decrease after 1995. From 2020 to 2050, soil erosion varied widely under different land use scenarios, and the land use pattern targeting ecological priority development would effectively mitigate soil erosion. Therefore, optimizing land use patterns and structures are critical initiatives to prevent soil erosion.

Settlement suitability analysis of a riverine floodplain in the perspective of GIS-based multicriteria decision analysis

Riverine floodplains are highly dynamic and the most vulnerable space on Earth particularly in flat alluvial plains of major river systems. Suitable site selection for sustainable human settlements in active floodplain areas is a critical task for decision-makers in terms of quality of lithology, ecologically fragile landmass, climate-induced hazards, immense population pressure, and environmental conservation issues. This research introduces a methodology for settlement suitability zone (SSZ) that employs GIS-based multi-criteria decision-making (MCDM) techniques. As a case study, an altered hydrological regime of the lower Ganga riparian zone was chosen to identify the SSZ as these areas are the most susceptible to riverine hazards. Twelve significant variables reflecting on topography, climate, landscape, and environment have been selected in the multi-criteria evaluation platform. The CRiteria Importance Through Intercriteria Correlation (CRITIC) method is adopted to specify the weights of the criteria and utilize an inverse distance-weighted (IDW) spatial interpolation technique to generate an SSZ map in a GIS environment. The study zone is spatially quantified into five categories, from unsuitable to high-suitable with a natural breaks (Jenks) classification method. Subsequently, the final results are validated through a receiver operating characteristics (ROC) curve using randomly selected 56 hazard-exposed location points. The outcome revealed that 8.45% of the riparian area falls under unsuitable, 21.87% under low-suitable, and 33.27% under moderate-suitable for locating human settlements. The generally suitable and high-suitable categories account for 36.40% of the total study zone. A spatial sensitivity analysis is also applied to gauge the influence of each parameter on the MCDM outcomes. The SSZ mapping results from this study can help local authorities to plan for sustainable settlement development in environmentally fragile areas.

Sediment routing system and sink preservation during the post-orogenic evolution of a retro-foreland basin: The case example of the North Pyrenean (Aquitaine, Bay of Biscay) Basins

Abstract We investigated here the evolution of the sediment routing system, i.e. the sediment transport and deposition evolution along successive depositional topographies and environments, and the sink (i.e. deposited sediments) preservation in a foreland basin from the period of mountain belt shortening to its post-orogenic stage. The studied system is the North Pyrenean retro-foreland basin from 50 Ma to today which is, composed of a subsiding platform (the Aquitaine Basin) fed by the erosion of the Pyrenees passing laterally to a slope and a deep-sea plain (the Bay of Biscay deep basin), the ultimate area of deposition. This study is based on a double seismic stratigraphic and structural analysis of an extensive seismic dataset and on an age model of the sediments combining biostratigraphy, orbitostratigraphy and sequence stratigraphy with a time resolution of 0.1 Ma. Four major periods of deformation corresponding to a single or a set of stratigraphic sequence boundaries were characterized. The Pyrenean shortening decrease may be recorded by a basin-scale uplift at 49.8 Ma (Late Ypresian). The paroxysm of the piggy-back shortening and related uplift is dated at 35.8 Ma (Priabonian). The end of the Pyrenees shortening (transition to post-orogenic conditions) is well dated between 27.1 and 25.2 Ma (Chattian). A major West European scale deformation of possible mantle origin uplifted the basin from 16.4 to 10.6 Ma (Late Burdigalian to Early Tortonian). These major periods of deformations controlled the sink preservation at the first order through the ratio between the accommodation space created by subsidence on the Aquitaine platform (Asub) and the siliciclastic sediment supply coming from the erosion of the Pyrenees (Ssc). A general model is proposed. At the time of the foreland basin when ΔAsub ≤ ΔSsc, most of the sediments are preserved on the platform as a progradational-aggradational wedge (up to 25.2 Ma here). At the time of the post-foreland evolution when ΔAsub The continental sediment routing system is mainly provided along nearly flat alluvial plains with extensive lakes and/or humid zones, i.e. the local base levels of the alluvial fans. The Aquitaine retro-foreland was never overfilled.

Fisheries-Based Ecotourism in Bangladesh: Potentials and Challenges

Recreational fishing trips constitute a significant part of the tourism business in many countries. Linking fisheries to tourism can be both a response to the need to create innovative tourism products and the need to find new sources of income for fisheries to make them more profitable and sustainable. This leads to the question of whether Bangladesh can be developed as a Fisheries-Based Ecotourism (FbE) destination. Though several types of research have been done concerning the prospects of ecotourism in Bangladesh, the feasibility of FbE specifically remains under-studied. Based on a literature review and stakeholder interviews, this study explores the concept of FbE in a Bangladeshi context and its potential impacts on socio-economic community life as well as on the environment. This paper makes the case that the diversified topography of Bangladesh—including the riverine flat alluvial plains, hills and valleys, deciduous and evergreen forests, lakes, seashores, and beaches—is ripe with potential for FbE development. With its focus on the prospects and challenges of FbE development in Bangladesh, this paper could provide a useful reference point for future discourse on these sorts of cultural and economic strategies.

The use of HVSR measurements for investigating buried tectonic structures: the Mirandola anticline, Northern Italy, as a case study

The Mirandola anticline represents a buried fault-propagation fold which has been growing during Quaternary due to the seismogenic activity of a blind segment belonging to the broader Ferrara Arc. The last reactivation occurred during the May 2012 Emilia sequence. In correspondence with this structure, the thickness of the marine and continental deposits of the Po Plain foredeep is particularly reduced. In order to better define the shallow geometry of this tectonic structure, and hence its recent activity, we investigated in a depth range which is intermediate between the surficial morphological observations and seismic profiles information. In particular, we carried out numerous passive seismic measurements (single-station microtremor) for obtaining the horizontal-to-vertical spectral ratio. The results of a combined analysis of the peak frequency and its amplitude nicely fit the available geological information, suggesting that this low-cost geophysical technique could be successfully applied in other sectors of wide morphologically flat alluvial plains to investigate blind and completely buried potential seismogenic structures.

Livelihood Dynamics as a Response to Natural Hazards: A Case Study of Selected Places of Basanti and Gosaba Blocks, West Bengal

The Indian Sundarban with a shore length of 130 km is topographically a low lying flat alluvial plain, dissected by a large number of tidal rivers, estuaries and creeks. The reclamation activity in the islands of Sundarbans for resource generation and resource consumption was accentuated in the latter half of the 19th century replacing mangroves by the Colonial Government of India. The premature reclamation was done by raising embankments all along the river banks which has reduced the spill areas of rivers leading to in channel siltation. Thus the tidal floodplain, devoid of silt is always at a lower level than the water level of the rivers. Moreover the creeks of Sundarban are severed from their freshwater upland sources and record increase in salinity. Comparison of data of 1984 and that of 2001 shows drastic increase in the salinity of the outer estuary (26 ppt to 36.2 ppt) and that of mid estuary from 20 ppt to 26 ppt for summer of the eastern sector. (Chand et al, R. K Trivedi, S. K. Dubey and M. M. Beg, 2012) Ref [4]. The study area comprising of places Hogolduri, Kalahazra, Katrakhali, Bagulakhali, Chunakhali, Parbatipur, Masjidbati of Basanti block and Sambhunagar of Gosaba block of West Bengal, India are highly vulnerable to hazards and disasters like tropical cyclones, embankment breaching and subsequent salt water incursion. This has led to occupational shift as agricultural lands are transformed to aquaculture farms. This paper takes into account this budding problem over the years and studies the livelihood pattern of the study area. Survey Of India toposheets of 1969 (79 B/12, 79 B/15 and 79 B/16) followed by satellite images (LANDSAT 4, 5 and LANDSAT 7, Path – 138, Row – 45, from USGS Earth Explorer) and Google Earth imageries have been used. Questionnaire surveys have also been conducted. It has been found that the area of aquaculture farms have been increasing at the cost of agricultural lands. Since the transformation of agricultural lands to aquaculture farms is permanent and the people need to adapt to this transformation, it is highly recommended to run the aquaculture farms on a co – operative basis so that the profits will be distributed among the stakeholders according to their share of land.

Multi-scale monitoring of landscape change after the 2011 tsunami

Abstract. The Great East Japan Earthquake (magnitude 9.0; occurred on 11th March 2011) and subsequent huge tsunami caused widespread damage along the Pacific Ocean coast of eastern Honshu, Japan. This research utilizes multi-resolution remote sensing images to clarify the impact on landscapes caused by this disaster, and also to monitor the subsequent survival and recovery process in the Sendai Bay region. The coastal landscape in the target area features a narrow strip of coastal sand barrier, historically stabilized by planted pine groves; backed by a low-lying plain that has traditionally been diked and converted to irrigated rice paddies. Farmsteads on the flat alluvial plain are surrounded by groves called “Igune”, consisting primarily of conifers. MODIS data (250 m resolution) were employed to map the overall extent of inundation and damage on the regional landscape scale. The major damage caused by the tsunami, destruction of coastal pine forests and inundation or rice paddies on the plain, was identified at this level. Progressively finer scale analysis were then implemented using SPOT/HRG-2 (10 m resolution) data; GeoEye-1 fine resolution data (0.5 m) and very fine resolution aerial photographs (10 cm) and LiDAR. These results demonstrated the minute details of the damage and recovery process. Some patches of pine forest, for example, were seen to have survived, and some coastal plant communities were already recovering only a year after the disaster. Continuous monitoring using field work and remote sensing is required for balanced regional strategies that provide for economic and social recovery and as well as restoration of vegetation, biodiversity and vital ecosystem services.

Mass Movement-Induced Tsunami Hazard on Perialpine Lake Lucerne (Switzerland): Scenarios and Numerical Experiments

Previous studies of the sediments of Lake Lucerne have shown that massive subaqueous mass movements affecting unconsolidated sediments on lateral slopes are a common process in this lake, and, in view of historical reports describing damaging waves on the lake, it was suggested that tsunamis generated by mass movements represent a considerable natural hazard on the lakeshores. Newly performed numerical simulations combining two-dimensional, depth-averaged models for mass-movement propagation and for tsunami generation, propagation and inundation reproduce a number of reported tsunami effects. Four analysed mass-movement scenarios—three based on documented slope failures involving volumes of 5.5 to 20.8 × 106 m3—show peak wave heights of several metres and maximum runup of 6 to >10 m in the directly affected basins, while effects in neighbouring basins are less drastic. The tsunamis cause large-scale inundation over distances of several hundred metres on flat alluvial plains close to the mass-movement source areas. Basins at the ends of the lake experience regular water-level oscillations with characteristic periods of several minutes. The vulnerability of potentially affected areas has increased dramatically since the times of the damaging historical events, recommending a thorough evaluation of the hazard.

Examining the spatial and temporal variation of groundwater inflows to a valley-to-floodplain river using <sup>222</sup>Rn, geochemistry and river discharge: the Ovens River, southeast Australia

Abstract. Radon (222Rn) and major ion geochemistry were used to define and quantify the catchment-scale groundwater-surface water interactions along the Ovens River in the southeast Murray–Darling Basin, Victoria, Australia, between September 2009 and October 2011. The Ovens River is characterized by the transition from a single channel within a mountain valley in the upper catchment to a multi-channel meandering river on flat alluvial plains in the lower catchment. Overall, the Ovens River is dominated by gaining reaches, receiving groundwater from both alluvial and basement aquifers. The distribution of gaining and losing reaches is governed by catchment morphology and lithology. In the upper catchment, rapid groundwater recharge through the permeable aquifers increases the water table. The rising water table, referred to as hydraulic loading, increases the hydraulic head gradient toward the river and hence causes high baseflow to the river during wet (high flow) periods. In the lower catchment, lower rainfall and finer-gained sediments reduce the magnitude and variability of hydraulic gradient between the aquifer and the river, producing lower but more constant groundwater inflows. The water table in the lower reaches has a shallow gradient, and small changes in river height or groundwater level can result in fluctuating gaining and losing behaviour. The middle catchment represents a transition in river-aquifer interactions from the upper to the lower catchment. High baseflow in some parts of the middle and lower catchments is caused by groundwater flowing over basement highs. Mass balance calculations based on 222Rn activities indicate that groundwater inflows are 2 to 17% of total flow with higher inflows occurring during high flow periods. In comparison to 222Rn activities, estimates of groundwater inflows from Cl concentrations are higher by up to 2000% in the upper and middle catchment but lower by 50 to 100% in the lower catchment. The high baseflow estimates using Cl concentrations may be due to the lack of sufficient difference between groundwater and surface water Cl concentrations. Both hydrograph separation and differential flow gauging yield far higher baseflow fluxes than 222Rn activities and Cl concentrations, probably indicating the input of other sources to the river in additional to regional groundwater, such as bank return flows.

Selection of Groundwater Control Scheme for Deep Excavation in Alluvial Soil along the Yellow River

Kaifeng locates on a flat and open alluvial plain of the middle and lower reaches of the Yellow River. Owing to its complex history and long-term deposition, a silty stratum with multi-miscellaneous fill and alluvial soil interphase is gradually formed. Combing with the soil actual characteristics of Kaifeng area, which is mainly composed of “high water content”, “high water head”, “strong permeability”, “low strength”, “adequate water supply”, a optimal groundwater control scheme for deep excavation under above complicated geological conditions is proposed. Moreover, the most appropriate waterproof curtain form is recommended for the foundation pit engineering whose excavation depth is less than 10m. The findings of this investigation may offer some suggestions for the choice of groundwater control scheme for construction purpose in similar strata.

Spatial distribution of pipe collapses in Goodwin Creek Watershed, Mississippi

AbstractThe internal erosion of soil pipes can induce pipe collapses that affect soil erosion processes and landform evolution. The objective of this study was to determine the spatial distribution of pipe collapses in agricultural fields of Goodwin Creek watershed. Ground survey was carried out to detect pipe collapses, and the location, size and surface elevation was measured with differential GPS. A total of 143 of the 145 pipe collapses were found in cropland, and the density was approximately 0.58 collapses per hectare. The spatial distribution of pipe collapses was not uniform as pipe collapses were concentrated in the flat alluvial plains where the land use was dominated by cropland. One of the four parcels had 90% of the pipe collapses with a density of 7.7 collapses per hectare. The mean depth, area and volume of these pipe collapses were 0.12 m, 0.34 m2 and 0.02 m3, respectively, and all these properties exhibited a skewed distribution. The drainage area–slope gradient equation, which has been widely used for erosion phenomenon prediction, did not represent pipe collapses in this study as the coefficient of determination was <0.01. This is clear evidence that subsurface flow is not represented by surface topographic characteristics. The pipe collapses were found to intercept runoff, thereby reducing the slope length factor by 6% and the drainage area by 7%. Both of these factors can reduce the sheet and rill erosion; however, the increased subsurface flow could enhance ephemeral gully erosion. Published 2012. This article is a U.S. Government work and is in the public domain in the USA.

Physiographic soil map delineation for the Nile alluvium and desert outskirts in middle Egypt using remote sensing data of EgyptSat-1

The objectives of this study are to produce a physiographic soil map with correlated attributes to be a base for extra modifiers within the land information system. This integrated data will serve the purposes of land use planning, precision farming practices and to be applied in other areas using the extrapolation approach. The Satellite data of EgyptSat-1 were projected on an area of Middle Egypt that represents unique physiographic features over portions of Beni Suef, El Fayoum, Helwan, and October Provinces. The spectral signatures of the land patterns were delineated by the visual interpretation using the physiographic approach, while soil taxa were categorized according to the key of Soil Taxonomy ( USDA, 2010), resulting in two landscape categories. The first category includes older and developed parent materials, covering the following units: (a) Pediplains of residual soils over limestone parent rock, having soils of Lithic Haplocalcids, loamy skeletal. (b) Terraced old alluvial plains represent the formerly deposited alluvium that preceded the recent one of the River Nile alluvium. They includes soils of Typic Calcigypsids, loamy skeletal and old alluvial plain but are currently managed under cultivation. The soils are dominated by Typic Haplocalcids, loamy skeletal. (c) Wadis that were shaped by the paleodrainage erosion, are currently subjected to the seasonal flush flooding and are sparsely vegetated including soils of Typic Torrifluvents, lamy skeletal (calcareous); Typic Torriorthents, sandy skeletal, and Typic Torriorthents, sandy. (d) Aeolian plain “partly cultivated” includes soils of Typic Torripsamments (calcareous). The second category is a recent River Nile alluvium that formed the following units: (a) Terraced recent alluvial plain “cultivated” includes soils of Entic Calcitorrerts, fine and Typic Haplotorrerts fine. (b) Recent flat alluvial plain includes soils of Typic Haplotorrerts, fine. (c) Meandering belt is aligning the River Nile course with courser sediments comparing to the recent alluvial plains. This belt is sub divided as levees that have soils of Typic Torriorthents, fine lomy; point bars with soils of Typic Torriorthents, coarse lomy; river banks with soils of Typic Torriorthents, coarse lomy; bow bars with Typic Torriorthents, sandy and Typic Torriorthents, coarse loamy and meander scars with soils of Typic Torriorthents, sandy. All these taxonomic classes are hyperthermic, being developed under the hyperthermic temperature regime within an aridic moisture regime.

AQMOD: Hydrogeological Study of Aquifers in the Bojana Delta, Montenegro

AQMOD: Hydrogeological Study of Aquifers in the Bojana Delta, Montenegro

Holocene palaeoenvironmental changes in Agia Paraskevi prehistoric settlement, Lamia, Central Greece

Holocene palaeoenvironmental changes in the area of the prehistoric settlement of Megali Vrysi close to the village of Agia Paraskevi in Central Greece, 5 km east of Lamia City, were investigated. The area is situated in the low flat alluvial plain on the outskirts of Sperchios Valley that is bordered NNW to ENE by a rocky, hilly ridge of the Othrys Mountain foothills, 5.5 km away from the present coastline. The Megali Vrysi site is considered to be an important Mediterranean prehistoric commercial centre. Reconstruction of the palaeoenvironmental changes of the broader area adds new information concerning the general palaeogeographical setting of the settlement. Multidisciplinary research involved a detailed geomorphological survey combined with stratigraphical, palaeontological, and geophysical studies. The penetrated strata differentiated into 4 units from top to bottom. The first represents the archaeological strata. The second consists of the freshwater marshy sediments, while the third is the transition layer between the second and the deeper fourth group of marine – lagoonal sediments. The Holocene stratigraphy data was combined with the 14C-AMS dating results and showed a marine palaeoenvironment (∼ 5500 BC) gradually having shifted to a coastal – lagoonal one (∼3500 BC) and finally changed to a freshwater marshy environment (∼2500 BC). The comparison between ages and depths of the relative sea level points allowed the estimation of the sea level rise rate for the Agia Paraskevi area which is considerably lower than the one proposed for the Aegean Sea in the same time period. This considerable offset is attributed to the intensive tectonic uplift of the study area due to the tectonic deformation of the Sperchios Valley and this is probably why the prehistoric coastal settlement remained on the surface and unaffected from the sea transgression for more than 7000 yrs during Holocene.

Recent seismogenic fault activity in a Late Quaternary closed-lake graben basin (Albacete, SE Spain)

The Cordovilla basin, located within the frontal thrust belt of the Betic Cordillera, SE Spain, is an elongated NW–SE graben showing discrete surface rupture generated by Holocene paleoearthquake activity. A main and an antithetic normal, NW–SE trending, active faults bound the basin. Paleoseismological evidence is reported on upslope-facing scarps of the antithetic fault, acting as dams to runoff, which contributed to temporary lacustrine conditions, as well as sediment uplift. The fluvial network in the area shows a poor drainage activity, whereas a present lake is dammed by the antithetic fault. The modern landscape is controlled by Holocene faulting, modifying the geological environment according to earthquake occurrence, from flat alluvial plains to lacustrine local basins. The application of the diffusion dating technique to unconsolidated sediments for the antithetic fault scarp indicates an age between 1 and 2 ka. Various geometric parameters have been obtained in order to reconstruct the paleoseismic history of the Cordovilla graben basin. The surface rupture and fault-offset values are associated with discrete active morpholineaments, parallel to the Pozohondo Fault. The Tobarra–Cordovilla segment (the structural boundary of the Cordovilla Basin) was generated by earthquakes with magnitudes (Mw) greater than 6.0, based on Wells and Coppersmith fault scarp relations.

Response of active tectonics on the alluvial Baghmati River, Himalayan foreland basin, eastern India

Active tectonics in a basin plays an important role in controlling a fluvial system through the change in channel slope. The Baghmati, an anabranching, foothills-fed river system, draining the plains of north Bihar in eastern India has responded to ongoing tectonic deformation in the basin. The relatively flat alluvial plains are traversed by several active subsurface faults, which divide the area in four tectonic blocks. Each tectonic block is characterized by association of fluvial anomalies viz. compressed meanders, knick point in longitudinal profiles, channel incision, anomalous sinuosity variations, sudden change in river flow direction, river flow against the local gradient and distribution of overbank flooding, lakes, and waterlogged area. Such fluvial anomalies have been identified on the repetitive satellite images and maps and interpreted through DEM and field observations to understand the nature of vertical movements in the area. The sub-surface faults in the Baghmati plains cut across the river channel and also run parallel which have allowed us to observe the effects of longitudinal and lateral tilting manifested in avulsions and morphological changes.

Geomorphology of the Ganges fluvial system in the Himalayan foreland: an update

The Ganges is one of the largest fluvial systems in the world rising from the loftiest Himalaya and draining into the Bay of Bengal. Together with the Brahmaputra, it also constitutes the largest delta in the world before finally meeting the sea. The Ganges system passes through a variety of terrain from the rugged mountains through the flat alluvial plains and the sea margin, and also transects variable climatic zones. As a result, the processes, landforms and stratigraphy are strikingly different in different zones of the system. This paper attempts to provide an update on our understanding of this very large and diverse system. A global effort has been made in the last few decades, and the research has focused on a variety of themes. The mountainous catchments have attracted attention in view of the extent of glaciation and extensive erosional processes. The alluvial plains of the Ganges symbolizes the life line of one of the world's largest population. Consequently, a number of studies have been carried out on the morphology, hydrology including flooding history and sediment transport behaviour of the river system. The alluvial stratigraphy of the large valleys and the interfluves in the plains has provided insight about the sedimentation pattern and response to climate change. The deltaic plain is the final destination of this huge sediment dispersal system before it drains into the sea, and it also records the influence of sea level changes apart from the upstream catchment controls over a period of time.

Engineering the State: The Huai River and Reconstruction in Nationalist China, 1927 – 1937. By David A. Pietz. [New York and London: Routledge, 2002. ix+142 pp. £45.00. ISBN 0-415-93388-9.

Imperial China was known for its massive water control projects, most famously the Huang (Yellow) River dykes and the Grand Canal. Today's China is now constructing the largest hydroelectric project in human history, the Three Gorges dam. Sandwiched between these two eras was Republican China, when the traditional methods of construction and engineering gave way to new processes grounded in the principles of scientific hydrology and engineering largely developed in the West. In this brief but fascinating study, David A. Pietz examines the efforts of the Nationalist Government of Chiang Kai-shek during the Nanjing decade of 1927–1937 to re-shape the Huai River basin. A student of William Kirby, Pietz adopts the Kirby view that one should see 1949 not as an unbridgeable divide between two eras, but find much continuity in the growth of the modern developmental state in China.Pietz has chosen the Huai River basin for his case study primarily because it witnessed the Kuomintang government's largest such project. In addition, the ecology of no other area of China has been more impacted by human action. Although draining over a relatively flat alluvial plain, the Huai was far more stable in ancient times than its northern neighbor, the Huang River, because of a much lower silt content. Yet all changed in 1194 when the Huang broke through its banks and began to flow south into the Huai, radically altering the ecology of north central China. From 1194 until 1855 the Huang River entered the ocean through the old Huai River channel, rendering the Huai a mere tributary. Subsequent imperial governments attempted to contain the Huang River while at the same time stabilizing the Grand Canal, so essential for grain transport from the south.

Fluvial systems of the drylands of western India: a synthesis of Late Quaternary environmental and tectonic changes

The fluvial systems and landscape of the drylands of western India have preserved evidence of Late Quaternary environmental and tectonic changes. Data on the fluvial systems of Mainland Gujarat, Saurashtra and Kachchh have been synthesised to evaluate the roles of geological factors in the evolution of these drylands. Mainland Gujarat is largely underlain by the flat alluvial plain, and has a structurally controlled fluvial system that originates in the eastern uplands. The fluvial system of Mainland Gujarat shows deeply incised valleys, entrenched meanders, extensively developed ravines and uplifted terraces, which have preserved a Late Quaternary succession of continental (fluvial and aeolian) and marine sediments dating back to ∼125 ka . Marine sediments correspond to the transgressive phases of the last interglacial (∼125 ka) and post-glacial maximum (6 ka) . The overlying alluvial sediments suggest deposition by ephemeral rivers in varied fluvial depositional environments under a semi-arid to sub-humid climatic regime with periods of intense pedogenesis. The sedimentation can be correlated with marine isotopic stages (MIS) 5 and 3. The fluvial sediments are buried under a thick blanket of aeolian sediments, which are indicative of enhanced dune building activity in the Thar Desert and are correlatable to the global arid phase of the last glacial maximum. The post-aeolian tectonic uplift triggered severe erosion of Late Pleistocene sediments and 40– 50 m deep incised fluvial valleys were formed. This erosional phase suggests a resumption of fluvial activity, which coincided with the rapidly rising sea level on the west coast during the Early Holocene. The Holocene marine and fluvial aggradation was initiated within the incised fluvial valleys around 6 ka and continued uninterrupted until ∼2 ka . These sediments now occur as raised valley fill terraces suggesting a Late Holocene uplift further corroborated by low to moderate seismic activity during historical times. The landscape of Saurashtra is marked by flat-topped basaltic (trappean) ridges and a highly varied coastline where a narrow belt of low ridges and cliffs of miliolite limestones and other shore deposits are found. The fluvial system of Saurashtra shows a radial drainage pattern. The channels have steep banks in the hilly regions and show significant deflections before meeting the sea. Evidence of last interglacial high sea levels (∼125 ka) are found on the coastal cliffs of southern Saurashtra in the form of oyster reefs and notches of various types which now occur at higher levels. A net sea level rise of +7 m consistent with the global sea level estimates at 125 ka has been obtained by recent studies after decoupling the tectonic component. Dating of Late Pleistocene and Holocene sea levels on this coast suggest continued uplift of Saurashtra since 125 ka even though the sea level continued to fluctuate. The Holocene high sea submerged a considerable stretch of land including the Okha Rann on the northern Saurashtra coast and isolated patches in and around the river mouths on the southern coast. The short, straight and parallel courses of rivers in the direction of tectonic slope, incised and confined channel belts also suggest a strong component of tectonic uplift. The continental sediments exposed in these river valleys have however remained uninvestigated leading to lack of palaeoclimatic data. A remarkable control of structure on landscape evolution is depicted by the Kachchh peninsula. The fluvial system exhibits the characteristics of drainage flowing along tectonically provided slopes. The overall drainage pattern of Kachchh shows excellent correlation with N–S trending transverse fault patterns. The transverse fault system has brought out changes in the landscape of Kachchh though the Kachchh rift basin evolved along E–W latitudinal faults. The Quaternary deposits occur in the form of miliolite limestones, colluvial and alluvial fans, fluvial sands and silts, and Rann sediments. Significant sedimentologic details on these sediments are lacking. However, the marine incursions seem to correlate with the adjacent Saurashtra and Mainland Gujarat.