Measurement and modelling of evaporation from a coastal wetland in Maputaland, South Africa

Abstract. The contribution of freshwater supply from the Mfabeni Mire to Lake St. Lucia during dry periods is important to the survival of certain plant and animal species in the iSimangaliso Wetland Park. This freshwater supply is mainly dependent on the variability of the major components of the water balance, namely rainfall and total evaporation (ET). Attempts to quantify the water balance have been limited through uncertainties in quantifying ET from the Mfabeni Mire. Despite advances in evaporation measurement and modelling from wetlands, there still exists some doubt as to which methods are best suited to characterise wetland ET with most authors suggesting a combination of methods. In this study, the surface renewal (SR) method was successfully used to determine the long-term ET (12 months) from the Mfabeni Mire with calibration using eddy covariance during two window periods of approximately one week each. The SR method was found to be inexpensive, reliable and with low power requirements for unattended operation. The annual ET was lower (900 mm yr−1) than expected, due to cloud cover in summer and low atmospheric demand throughout the year, despite the available water and high windspeeds. Daily ET estimates were compared to the Priestley-Taylor results and a site specific calibration α = 1.0 was obtained for the site. The Priestley-Taylor results agreed well with the actual ET from the surface renewal technique (R2 = 0.96) throughout the 12 month period. A monthly crop factor (Kc) was determined for the standardised FAO-56 Penman-Monteith. However, Kc was variable in some months and should be used with caution for daily ET modelling. These results represent not only some of the first long-term measurements of ET from a wetland in Southern Africa, but also one of the few studies of actual ET in a subtropical peatland in the Southern Hemisphere. The study provides wetland ecologists and hydrologists with guidelines for the use of two internationally applied models for the estimation of wetland ET within a coastal, subtropical environment.

Download Full-text

Measurement and modelling of evaporation from a coastal wetland in Maputaland, South Africa

Hydrology and Earth System Sciences ◽

10.5194/hess-16-3233-2012 ◽

2012 ◽

Vol 16 (9) ◽

pp. 3233-3247 ◽

Cited By ~ 15

Author(s):

A. D. Clulow ◽

C. S. Everson ◽

M. G. Mengistu ◽

C. Jarmain ◽

G. P. W. Jewitt ◽

...

Keyword(s):

Cloud Cover ◽

Coastal Wetland ◽

Vapour Pressure Deficit ◽

High Water ◽

Early Morning ◽

Surface Renewal ◽

Area Index ◽

Water Users ◽

Sr Method

Abstract. The surface renewal (SR) method was used to determine the long-term (12 months) total evaporation (ET) from the Mfabeni Mire with calibration using eddy covariance during two window periods of approximately one week each. The SR method was found to be inexpensive, reliable and with low power requirements for unattended operation. Despite maximum ET rates of up to 6.0 mm day−1, the average summer (October to March) ET was lower (3.2 mm day−1) due to early morning cloud cover that persisted until nearly midday at times. This reduced the daily available energy, and the ET was lower than expected despite the available water and high average wind speeds. In winter (May to September), there was less cloud cover but the average ET was only 1.8 mm day−1 due to plant senescence. In general ET was suppressed by the inflow of humid air (low vapour pressure deficit) and the comparatively low leaf area index of the wetland vegetation. The accumulated ET over 12 months was 900 mm. Daily ET estimates were compared to the Priestley-Taylor model results and a calibration α = 1.0 (R2 = 0.96) was obtained for the site. A monthly crop factor (Kc) was determined for the standardised FAO-56 Penman-Monteith. However, Kc was variable in some months and should be used with caution for daily ET modelling. These results represent not only some of the first long-term measurements of ET from a wetland in southern Africa, but also one of the few studies of actual ET in a subtropical peatland in the Southern Hemisphere. The study provides wetland ecologists and hydrologists with guidelines for the use of two internationally applied models for the estimation of wetland ET within a coastal, subtropical environment and shows that wetlands are not necessarily high water users.

Download Full-text

The potential of a site-specific delivery of thiamine hydrochloride as a novel insect repellent exerting long-term protection on human skin: In-vitro, ex-vivo study and clinical assessment

Journal of Pharmaceutical Sciences ◽

10.1016/j.xphs.2021.07.017 ◽

2021 ◽

Author(s):

Mai El Halawany ◽

Randa Latif ◽

Alia Badawi

Keyword(s):

Human Skin ◽

Clinical Assessment ◽

Ex Vivo ◽

Thiamine Hydrochloride ◽

Insect Repellent ◽

Site Specific ◽

A Site ◽

Ex Vivo Study

Download Full-text

Long-term evaluation of coal fly ash and mine tailings co-placement: A site-specific study

Journal of Environmental Management ◽

10.1016/j.jenvman.2009.08.010 ◽

2009 ◽

Vol 91 (1) ◽

pp. 237-244 ◽

Cited By ~ 28

Author(s):

Muluken B. Yeheyis ◽

Julie Q. Shang ◽

Ernest K. Yanful

Keyword(s):

Fly Ash ◽

Mine Tailings ◽

Coal Fly Ash ◽

Site Specific ◽

Specific Study ◽

Term Evaluation ◽

A Site

Download Full-text

Engineering a light-controlled F1ATPase using structure-based protein design

PeerJ ◽

10.7717/peerj.2286 ◽

2016 ◽

Vol 4 ◽

pp. e2286 ◽

Cited By ~ 4

Author(s):

Daniel Hoersch

Keyword(s):

Protein Design ◽

Active Site ◽

Atp Hydrolysis ◽

Site Specific ◽

Dynamic Constraint ◽

End Distance ◽

A Site ◽

Hydrolysis Activity

The F1sub-complex of ATP synthase is a biological nanomotor that converts the free energy of ATP hydrolysis into mechanical work with an astonishing efficiency of up to 100% (Kinosita et al., 2000). To probe the principal mechanics of the machine, I re-engineered the active site ofE.coliF1ATPase with a structure-based protein design approach: by incorporation of a site-specific, photoswitchable crosslinker, whose end-to-end distance can be modulated by illumination with light of two different wavelengths, a dynamic constraint was imposed on the inter-atomic distances of the α and β subunits. Crosslinking reduced the ATP hydrolysis activity of four designs tested in vitro and in one case created a synthetic ATPase whose activity can be reversibly modulated by subsequent illumination with near UV and blue light. The work is a first step into the direction of the long-term goal to design nanoscaled machines based on biological parts that can be precisely controlled by light.

Download Full-text

Framework for an environmental safety case for geological disposal in the UK

Mineralogical Magazine ◽

10.1180/minmag.2012.076.8.59 ◽

2012 ◽

Vol 76 (8) ◽

pp. 3457-3464 ◽

Cited By ~ 1

Author(s):

M. J. Poole ◽

R. Kowe

Keyword(s):

Environmental Safety ◽

Approval Process ◽

Site Specific ◽

Geological Disposal ◽

Disposal Facility ◽

Safety Case ◽

The Uk ◽

A Site

AbstractThe implementation of a geological disposal facility requires the demonstration of confidence that such a facility would be safe during both the operational period and in the long-term after the closure of such a facility. The generic environmental safety case described in this paper is the vehicle used to demonstrate an understanding of environmental safety. It will be used to prepare a site-specific environmental safety case in due course. The approach taken will be consistent with a staged development and approval process, as advocated by the environmental regulators.

Download Full-text

Wildlife Conservation and Mangrove Interpretation Centre, Karamjal, Sundarban: A Case Study of a Site-Specific Architectural Project in a Mangrove Forest

Nakhara : Journal of Environmental Design and Planning ◽

10.54028/nj2019175570 ◽

2019 ◽

Vol 17 ◽

pp. 55-70

Author(s):

Farjana Rahman

Keyword(s):

Mangrove Forest ◽

Wildlife Conservation ◽

Coastal Wetland ◽

Site Specific ◽

Entry Points ◽

Ecological Consideration ◽

Reserve Forest ◽

Huge Impact ◽

A Site

This paper analyses the design process that addresses the ecological consideration and architectural factors with local indigenous materials so that nature-based tourism can be more encouraged and feasible towards sustainable development. The case study is the Sundarbans, which is a mangrove forest and coastal wetland with a complex ecosystem formed by a variety of plants and animals. Due to its diversity, ecosystem richness and uniqueness, this contiguous block has a huge impact on both local and global environment and is significant among researchers, conservationists and nature lovers. Karamjal, Bangladesh, one of the main entry points of Sundarban Reserve Forest is enriched with a diversified ecosystem. But now this site is deteriorating day by day with increasing unplanned build forms and visitors. For betterment of ecological setting and tourism facilities for global attention, Karamjal is indicative of better consideration both ecologically and architecturally. After analysis, a case study of site-specific design is proposed for improvement of this site.

Download Full-text

Site-specific variation in the potentiometric response to subsidence above active longwall mining

Environmental and Engineering Geoscience ◽

10.2113/gseegeosci.6.4.383 ◽

2000 ◽

Vol 6 (4) ◽

pp. 383-394 ◽

Cited By ~ 16

Author(s):

Colin J. Booth ◽

Alan M. Curtiss ◽

Philip J. Demaris ◽

Robert A. Bauer

Keyword(s):

Longwall Mining ◽

Jefferson County ◽

Site Specific ◽

Groundwater Levels ◽

Potentiometric Response ◽

Recharge Sources ◽

Longwall Panel ◽

Specific Variation ◽

A Site

Abstract Longwall underground coal mining produces major changes in the hydraulic properties and groundwater levels of overlying shallow aquifers because of the fracturing associated with mine subsidence. Many aspects of these impacts remain unclear and unpredictable, particularly the variations in response between different sites. Our detailed, long-term studies of subsidence strains and hydraulic responses at sites in Illinois address this and other aspects of the conceptual model. At a study site in Saline County, inconsistent permeability changes and large rapid head drops, without significant recovery, were observed in a low transmissivity sandstone over an active longwall panel. Corresponding head changes in overlying glacial drift units reflected localized drainage from the drift to the bedrock. In comparison to our earlier study at a site in Jefferson County, Illinois, in which full recovery occurred in a moderately transmissive sandstone aquifer affected by longwall mining, the Saline site illustrates the importance of local hydrogeologic characteristics, particularly variations in transmisivity and continuity with recharge sources, in controlling site-specific responses to longwall mining.

Download Full-text