An open source GIS‐based Planning Support System: Application to the land use plan of La Troncal,Ecuador

Planning Support Systems (PSS) comprise a wide variety of geo‐technological tools related to GIS and spatial modeling aimed at addressing land planning processes. This article describes the OpenRules system, a PSS based on a previous system called RULES. Among OpenRules new features are its architecture, based exclusively on free and open source software, and its applicability to all land use types, including rural and urban uses. In addition, OpenRules incorporates an unlimited number of land evaluation factors and a new objective in land use spatial allocation. OpenRules has been programmed in Java and implemented as a module of the free GIS software gvSIG, with full integration between the GIS and the decision support tools. Decision support tools include multicriteria evaluation, multiobjective linear programming and heuristic techniques, which support three basic stages of land use planning processes, namely land suitability evaluation, land use area optimization and land use spatial allocation. The application of OpenRules to the region of La Troncal, Ecuador, demonstrates its capability to generate alternative and coherent solutions through a scientific and justified procedure at low cost in terms of time and resources.     

Middle Pleistocene environments,landscapes and tephrostratigraphy of the Armenian Highlands: evidence from Bird Farm 1, Hrazdan Valley

The significance of the southern Caucasus in understanding Pleistocene hominin expansions is well established. However, the palaeoenvironments in which Palaeolithic occupation of the region took place are presently poorly defined. The Hrazdan river valley, Armenian Highlands, contains a rich Palaeolithic record alongside Middle Pleistocene volcanic, fluvial and lacustrine strata, and thus offer exciting potential for palaeoenvironmental reconstruction. We present the first results of sedimentological, geochemical, tephrostratigraphical and biological (diatoms) study of the sequence of Bird Farm 1, located in the central part of the valley. These data show six phases of landscape development during the interval 440–200 ka. The sequence represents the first quantitative Pleistocene diatom record from the Armenian Highlands and the southern Caucasus, and indicates the persistence of a deep, stratified lacustrine system, with evidence for changing lake productivity that is tentatively linked to climate. Furthermore, major element chemical characterization of visible and crypto-tephra horizons in the sequence enables the first stages of the development of a regional tephrostratigraphy. Together, the evidence from Bird Farm 1 demonstrates the importance of lacustrine archives in the region for palaeoenvironmental reconstruction and highlights the potential for linkages between archives on both a local and regional scale.     

Impact of road‐generated storm runoff on a small catchment response

The impact of road‐generated runoff on the hydrological response of a zero‐order basin was monitored for a sequence of 24 storm events. The study was conducted in a zero‐order basin (C1; 0·5ha) with an unpaved mountain road; an adjacent unroaded zero‐order basin (C2; 0·2 ha) with similar topography and lithology was used to evaluate the hydrological behaviour of the affected zero‐order basin prior to construction of the road. The impact of the road at the zero‐order basin scale was highly dependent on the antecedent soil‐moisture conditions, total storm precipitation, and to some extent rainfall intensity. At the beginning of the monitoring period, during dry antecedent conditions, road runoff contributed 50% of the total runoff and 70% of the peak flow from the affected catchment (C1). The response from the unroaded catchment was almost insignificant during dry antecedent conditions. As soil moisture increased, the road exerted less influence on the total runoff from the roaded catchment. For very wet conditions, the influence of road‐generated runoff on total outflow from the roaded catchment diminished to only 5·4%. Both catchments, roaded and unroaded, produced equivalent amount of outflow during very wet antecedent conditions on a unit area basis. The lag time between the rainfall and runoff peaks observed in the unroaded catchment during the monitoring period ranged from 0 to 4 h depending on the amount of precipitation and antecedent conditions, owing mainly to much slower subsurface flow pathways in the unroaded zero‐order basin. In contrast, the lag time in the roaded zero‐order basin was virtually nil during all storms. Copyright © 2009 John Wiley & Sons, Ltd.     

Effect of system variables and particle size on physical characteristics of air sparging plumes

Air was injected through a well in a thin transparent tank filled with saturated glass beads to study how the size and air saturation of air sparging plumes are affected by particle size and gradation; operational parameters such as injection pressure, well depth, injection pressure pulsing; and well outlet configuration. V-shaped air plumes with an apex between 40° and 60° were obtained for all tests. The air pressure required to initiate sparging agreed closely with the sum of the air entry pressure and the hydrostatic pressure, with higher initiation pressures required in the fine and well-graded beads. Higher air flow rates and air saturations were obtained in coarser beads at a given pressure, and the variation in flow rate was consistent with estimated air permeabilities. Peak average air saturations were 28–56% for the coarse-medium beads, 10% for the well-graded beads, and 8% for the fine beads. Air saturation and the radius of influence increased modestly (<40%) as the normalized injection pressure exceeded 0.1. Radius of influence increased by approximately a factor of two as the well depth increased, but leveled off once the ratio of radius of influence to well depth reached 0.60–1.05. Pulsing of injection pressure had no effect on the initiation pressure, air flow rate, or air saturation, but increased the size of the air plume and the radius of influence slightly (<15%). Well outlet configuration had only a slight affect the radius of influence (<10%), air saturation (<10%), or air flow rate (<12%). Dye testing showed that water surrounding the air plume circulated during continuous and pulsed sparging. However, pulsed sparging resulted in greater and more defined circulation of water within and adjacent to the air plume, which should reduce mass transfer limitations during sparging.     

The role of the individual producer in driving land change: the case of Santa Cruz, Bolivia, 1986–2006

The “neoliberal period” witnessed some of the largest forest clearing in Latin America, particularly in the relatively untouched eastern lowlands of sub-tropical Bolivia. This paper shows through the use of satellite imagery analysis that ~10,000 km² of forest were cleared during this time period (1986–2006) from an area of forest measuring ~55,000 km². It also shows through the use of semi-structured interviews that the role and the rationale of the individual producer was equally if not more important than structural adjustment policies and their accompanying effects in driving these changes. Producers decisions of how to use the land are influenced by their background and knowledge of production systems (“tradition”), physical and climatic factors, crops which require relatively little input and are easy to cultivate, soil and tillage factors, concerns over quantity of production, and government policies. The importance of this study lies in the fact that the factors which play an important role in land-use and land-cover change are complex and multivariable and include individual decisions of the producer which are sometimes external to the market and other outside influences. This study could possibly serve as an exemplar and a warning that conservationists and policy-makers should take heed of in the future. By focusing solely on macro-economic policies, we can often overlook the individual producer and their decision-making capacity to alter the landscape.     

Optical Response of the Atmosphere During the Caribbean Total Solar Eclipses of 26 February 1998 and of 3 February 1916 at Falcón state,Venezuela

An investigation of the optical response of the atmosphere before, during, and afterthe total solar eclipse of 26 February 1998 at the Caribbean Peninsula of Paraguaná (Falcón State) in Venezuela, was made by measuring photometrically the intensity of the sky brightness in three strategic directions: zenith, horizon anti-parallel or opposite the umbra path, and horizon perpendicular to this path. From these measurements, and by applying in an inverse way an empirical photometric model, very rough estimations of theextinction coefficient, and also of the average optical depth, were obtained in one of these particular directions. However based on meteorological measurements such as those of relative humidity and temperature, and applying a different model, a better estimation in the visual of the total global extinction coefficient of the sky (except the horizon), were made considering the contribution of each component: atmospheric aerosol, water vapour, ozone and Rayleigh scattering. It is shown that this global coefficient is mostly dependent upon aerosol extinction. In spite of the strong reduction of sky brightness photometrically observed during the totality, the results show that the sky was not dark. This is confirmed by the results obtained for the total global extinction coefficient. Additionally it is estimated that the total solar eclipse that took place also in Falcón State, Venezuela, at the beginning of the last century on 3 February 1916, was 30% darker that the 1998 eclipse, and that atmospheric aerosol played a relevant and similar role in the scattering of sunlight during the totality as it was for 1998's. Visual observations made during each event, which show that at length only one or two bright stars could be seen in the sky, support the results obtained for both eclipses.     

A reconstruction of the palaeohydrological conditions of a flood‐plain: a multi‐proxy study from the Grabia River valley mire,central Poland

This study investigated the Grabia River valley mire in central Poland to reconstruct its palaeoenvironmental conditions from the Younger Dryas to the present. We analysed sedimentological, biological and geochemical data from the palaeo‐oxbow lake and valley mire to identify the principal hydrological trends, especially episodes of high water level. During the Lateglacial and Holocene, the Grabia River had a meandering channel, and its hydraulic parameters and the channel dimensions changed in response to climatic oscillations and vegetation development. We identified phases of high flood intensity and high groundwater level that correlate with regional and supraregional climatic events. The frequency and timing of palaeohydroclimatic oscillations show strong similarities to records from other sites in Poland and the rest of Europe. We show that various analytical methods, namely, pollen, plant macrofossils, Cladocera, Chironomidae, sedimentological, geochemical and radiocarbon data, can be effective tools for reconstructing past hydroclimatic changes in palaeo‐oxbow lakes and investigating the effects of past climate changes on river environments. The high sensitivity of the biota, especially Cladocera, to changes in water level permits the reconstruction of palaeoecological changes, especially flood episodes that occurred in the river valley. In particular, the increase in the proportion of sediment‐associated Cladocera and pelagic taxa was closely correlated with floods. Through comparisons with the palaeobiological data, geochemical data allowed the identification of humid phases within the fen associated with a rising groundwater table, direct fluvial activity (floods) and alluvial deposition. We also discuss the limitations of palaeohydrological reconstructions based on these proxies, especially on fossil aquatic invertebrates.     

A chronological assessment of Lake Okeechobee (Florida) sediments using multiple dating markers

Reconstructing recent limnological history often relies on lead-210 dating to accurately ascribe a chronology to a sediment profile. In Lake Okeechobee, Florida, a large, shallow subtropical lake that may experience severe mixing, multiple dating methods are required to confirm that conformable sedimentation has been preserved and that the assumptions of the ²¹⁰Pb method are satisfied. This study uses stratigraphic profiles of heavy metals, ¹³⁷Cs, PCBs and pollen as independent dating markers to validate the sediment chronology as determined by ²¹⁰Pb for three cores from the central mud zone of the lake. Unsupported ²¹⁰Pb and most dating markers show distinct concentration/depth profiles, suggesting that the sediments have not been severely mixed for at least the last 75 years. Onset and maximum activity of the radioisotope ¹³⁷Cs in the cores coincides with the ²¹⁰Pb-dated interval of 1945–1970. This agrees well with the known timing of atmospheric deposition of ¹³⁷Cs that resulted from above-ground nuclear testing during late 1940s until 1963. Sediment core profiles of atmospherically deposited metals such as Zn and Pb, which reflect regional increases during industrialization and decreases after regulation in the 1970s, exhibit expected concentration increases and peaks coinciding within 5–15 years of the predicted ²¹⁰Pb dates. Uranium, a contaminant in some phosphate fertilizers, shows large concentration increases at core depths dated to be about 1950 by ²¹⁰Pb, matching the intensification of agriculture after WWII. PCBs, which are expected to peak in the early 1970s, were measured in one core, and the observed peak corresponds to a ²¹⁰Pb date of about 1960. Pollen makers were unable to verify specific events, but increases in disturbance taxa and declines in native types correspond generally with the expected dates assigned by ²¹⁰Pb dating. Conformity between the ²¹⁰Pb defined dates and independent markers of < ±15 years confirm that Lake Okeechobee sediments do preserve a sequential and reliable stratigraphic history of the lake, useful for reconstructing past limnological conditions.