Integrated aquaculture systems (IAS) are a type of recirculating aquaculture systems (RAS) where the wastewater is treated and returned to the fish tanks. The important difference between the two is that in an IAS, wastes from the aquaculture component are recovered as fertilizer to produce an agricultural product whereas in an RAS, waste organics, nutrients and solids are treated and discharged. A pilot marine IAS at Mote Aquaculture Research Park in Sarasota, FL was studied for this project. Water quality monitoring, measurements of fish health and growth rates of fish and plants were performed over a two-year period to determine the effectiveness of the system in producing fish and plant products and removing pollutants. The goal of this portion of the project was to develop, calibrate and evaluate a model of the system, to understand the nitrogen transformations within the Mote IAS and to investigate other potential configurations of the Mote IAS. The model was divided into the various compartments to simulate each stage of the system, which included fish tanks, a drum filter for solids removal, and moving bed bioreactor (MBBR) for nitrification and disinfection. A solids tank after the drum filter was used to store the drum filter effluent slurry, which was then divided between three treatment processes: a geotube, a sand filter followed by a plant bed, and a plant bed alone. Nitrogen species modeled were particulate organic nitrogen (PON), dissolved organic nitrogen (DON), ammonium and nitrate. Of the physical components of the IAS, models of the MBBR and the two plant raceways included physical, chemical and biological nitrogen transformation processes. The sand filter, solids tank and geotube models were simple mass balances, incorporating factional removals of each species based on the observed data. Other variables modeled included temperature, dissolved oxygen, volatile suspended solids and chemical oxygen demand concentrations. The model was built in a computer program, STELLATM, to simulate the Mote IAS. The model calibration involved experimental, literature and calibrated parameters. Parameters were adjusted until the model's output was a best fit to the observed data by minimizing the sum of the squared residuals. During the sensitivity analysis, two model parameters caused large variations in the model output. The denitrifier constant caused the most variation to the model's output followed by the denitrifier fraction of volatile suspended solids. Of the removal processes, denitrification was the largest nitrogen removal mechanism from the model, accounting for 59% and 55% of the nitrogen removed from the south and north plant raceways respectively. Plant and soil uptake represented only 0.2% of the overall nitrogen removal processes followed by 0.1% by sedimentation. Finally, the model was used to investigate other treatment designs if the Mote IAS was redesigned. The first option involved a geotube and one plant raceway in series to treat the solid waste while the second option did not have a geotube, but two plant raceways. The first option was the most effective at removing nitrogen while the second was as effective as the original system and would cost less.

 This study primarily aimed to evaluate the usefulness of fatty acids (FAs) in revealing trophic relationships in Hong Kong wetlands, through a combination of field studies and laboratory experiments. A field-based study in Mai Po mangroves involved FA profiling of basal food sources (i.e., leaf litter from three mangrove species, diatoms and macroalgae, and sediments) and consumers (particularly crabs). FA composition of all mangroves was similar, and lacked some polyunsaturated FAs present in diatoms and macroalgae. Uca and Sesarma crabs, with different feeding mechanisms, had divergent FA profiles: Uca arcuata FAs reflected a diet of macroalgae and diatoms, while FAs of Sesarma spp. were typical of mangrove leaves. Temporal changes in consumer FA profiles between 2001 and 2007 appeared attributable to increased sedimentation at Mai Po and shifts in organic content of the substratum. A second field-based study was conducted at Luk Keng marsh where a salinity gradient (0 to 30?) allowed investigation of the effects of salinity changes in FA profiles and stable isotope (carbon and nitrogen) signatures of the consumers and their foods. Basal food sources were leaf litter, including a fungal biomarker of decomposition (ergosterol), fine particulate organic matter (FPOM) and periphyton. Both FPOM and periphyton (but not leaf litter) contained 20:4 and 20:5 FAs, but their concentrations were affected by salinity. FA 20:4 occurred at higher levels in samples from fresh water, whilst FA 20:5 exhibited the opposite pattern and was more abundant under saline conditions, and thus the ratio of FA 20:4 to FA 20:5 decreased with increasing salinity. Combined application of FA biomarkers and isotopic signatures were able to elucidate trophic relationships between consumers and their food at Luk Keng confirming that FA 20:4 as a useful biomarker in the freshwater portion and FA 20:5 in the more saline area. FA 20:4 was particularly associated with predatory freshwater insects that had high δ15N values, but was scarce in primary consumers (snails, detritivorous beetles) with low δ15N values. Two laboratory experiments were undertaken to investigate: 1) the effect of diet on FA profiles in the apple snail, Pomacea canaliculata, and 2) interacting effects of diet and salinity on FA profiles of the Indian medaka fish, Oryzias melastigma. The results of the apple snail study showed that dietary-mediated changes in FA profiles were only reflected in the snail tissues after at least three months, and FA profiles of digestive tissues and neutral lipids were first to respond to the dietary change. The results of the medaka study demonstrated that the ratio of FA 20:4 to FA 20:5 was affected by both diet and salinity, reflecting a similar finding in the Luk Keng field study, although diet had a stronger effect on this ratio. The results of both field studies supported the use of FA profiles as food web tracers in wetlands and were complemented by laboratory results that yielded insights which will allow refinement of FA biomarker applications in food-web studies. / published_or_final_version / Biological Sciences / Doctoral / Doctor of Philosophy

Agricultural practices have altered natural wetland habitats for thousands of years in lowland areas of Southeast Asia, and currently these highly modified wetlands constitute some of the most important remaining habitats for amphibians. However, decreasing area of arable land and increased use of chemicals may affect the persistence of lowland amphibian populations that are now dependent on these habitats. I investigated how amphibians responded to different kinds of farming treatments in a large agricultural wetland in Hong Kong. In the first part of the study, I assessed the occurrence of breeding amphibians in 53 farming plots in 2010 and 2011. Anuran call surveys were conducted at night at the plots once a week from March to August for two years. Environmental variables were measured and used to develop models to examine species presence, occupancy, and detection probabilities. Wet agricultural plots supported 10 species of amphibians and all had detection probabilities of < 1 that varied seasonally and yearly. Organically managed plots and shallow water plots yielded high species richness and particularly attracted the ornate pygmy frog (Microhyla fissipes) and the paddy frog (Fejervarya limnocharis). Air temperature and humidity were the relatively consistent predictors that influenced calling activity of the four most commonly detected species (M. fissipes; F. limnocharis; brown tree frog Polypedates megacephalus; and G?nther’s frog Hylarana guentheri). For the second part of the study, I assessed the impacts of fertilizers on amphibians. Using mesocosm experiments in the field, I compared the effects of a chemical fertilizer (granular urea) and an organic fertilizer (peanut cake) on the survival and growth of hatchlings of Polypedates megacephalus, the marbled pygmy frog (Microhyla pulchra), Asian common toad (Duttaphrynus melanostictus) and Chinese bullfrog (Hoplobatrachus rugulosus). Fertilizers were applied at low, manufacturer-recommended, and high levels, and survival and snout-vent-length were measured after 21 days. No individuals survived in the chemical fertilizer treatment at the recommended application level. Conversely, survival was high for P. megacephalus (96%), M. pulchra (54%) and D. melanostictus (90%), but relatively low for H. rugulosus (18%), at the recommended level of the organic fertilizer. P. megacephalus and M. pulchra tadpoles showed increased growth in elevated concentrations of organic fertilizer. Polypedates megacephalus tadpoles were 1.6 times longer in the low concentration and almost double in length in the high concentration treatments. Similarly, increased growth in M. pulchra in all organic treatments resulted in abbreviated time to metamorphosis. Chemical fertilizers are clearly detrimental to early life stages of these amphibians, but organic fertilizers may confer benefits including a shorter time to, and larger size at, metamorphosis. These results suggest that where amphibian conservation is a priority, shifts in the management of wet agricultural crops and limiting the use of chemical fertilizers may increase the suitability of breeding habitats and survival at early life stages. / published_or_final_version / Biological Sciences / Master / Master of Philosophy

Conserving ecologically important sites under private ownership has long been the problem to the Government. In Mai Po and Inner Deep Bay Ramsar Site, wetland habitat comprises of a number of fishponds under private ownership. The land ownership issue hinders these fishponds from wetland conservation. Conventional conservation approach, which relies on nature reserve designation and land acquisition, is not always applicable due to huge financial implication. To resolve the issue, the Government launched Public-private Partnership Scheme in 2004, to encourage wetland conservation projects on private lands through integration of wetland conservation and development. In recent years, projects applied through Public-private Partnership Scheme have received strong objection from the public and green groups. They criticize the projects will impose potential impacts on wetland habitat and threats on biodiversity values. This study identified the inadequacies of Public-private Partnership Scheme and to analyze the root causes leading to ineffectiveness. The result of evaluation found several inadequacies in Public-private Partnership Scheme, including (i) ignorance of overall biodiversity values; (ii) weak linkage between conservation and development objectives and result in incompatible land uses; (iii) neglected the interest of powerless stakeholders in the design of trade-off and incentives; (iv) lacks of other policies, cross-departmental and regional planning supports; (v) uncertainty in long-term financial arrangement; and (vi) top-down and unidirectional participation process. These inadequacies are further categorized into five root causes leading to ineffectiveness of PPP scheme, including (i) limitations of incentive, (ii) lack of clear conservation targets, (iii) passive and rigid mechanism, (iv) top-down participation process, and (v) project-based policy. Based on these root causes, the Government’s motivation in conservation is much lag behind when compared to the public expectation. Its effort in facilitation is limited and critically influences the effectiveness of Public-private Partnership Scheme. Its passive and supervision role of the Government hinder the mechanism of Public-private Partnership Scheme search for better integration of wetland conservation and development. / published_or_final_version / Urban Planning and Design / Master / Master of Science in Urban Planning

published_or_final_version / Architecture / Master / Master of Landscape Architecture

Balm Road Treatment Marsh is a 12 ha constructed wetland treatment system in south-central Hillsborough County, Florida created to improve water quality in Bullfrog Creek and ultimately Tampa Bay. The treatment system was designed to treat runoff from approximately 741 ha of upstream agricultural land prior to discharging into the creek, with the primary goals of reducing sediment and nutrient loads. Water quality data from four sites on Bullfrog Creek were analyzed to determine impacts to ambient water quality and pollutant load reductions downstream. Results were compared to the performance of other wetlands to treat both nonpoint and point source pollution. Impacts to ambient water quality in the creek were found to be minimal, if any, and although significant load reductions were found downstream, they could not be attributed to wetland treatment affects with confidence. In general, nonpoint source pollution, particularly from agriculture, was found to be treated less effectively than point sources. The importance of monitoring the performance of stormwater projects while employing a strategic sample design and including receiving water impacts is highlighted.

The hydrology of the Canadian Prairies has been well described in the scientific literature. 20th C observations show that snowmelt over frozen soils accounted for over 80% of the annual runoff, and streamflow hydrographs peaked in April and ceased in May due to a lack of runoff or groundwater contributions. Since then, the region has undergone rapid changes in land use and climate, both which affect streamflow generating processes. This study evaluates the detailed hydrological impact of regional changes to climate on an instrumented research catchment, the Smith Creek Research Basin (SCRB); an unregulated, wetland and agriculture dominated prairie catchment in south-eastern Saskatchewan. Wetlands have been drained for decades, reducing wetland extent by 58% and maximum storage volume by 79%, and increasing drainage channels lengths by 780%. Long term meteorological records show that there have been gradual changes to the climate: though there are no trends in annual precipitation amount, increasing temperatures since 1942 have brought on a gradual increase in the rainfall fraction of precipitation and an earlier snowmelt by two weeks. In the summer months, the number of multiple day rainfall events has increased by 5 events per year, which may make rainfall-runoff generation mechanisms more efficient. Streamflow records show that annual streamflow volume and runoff ratios have increased 14-fold and 12-fold, respectively since 1975, with major shifts in 1994 and 2010. Streamflow contributions from rainfall-runoff and mixed-runoff regimes increased substantially. Snowmelt runoff declined from 86% of annual discharge volume in the 1970’s to 47% recently while rainfall runoff increased from 7% to 34%. Annual peak discharge tripled over the period from 1975 to 2014, with a major shift in 1994, while the duration of flow doubled in length to 147 days after a changepoint in 1990. Recent flooding in the SCRB has produced abnormally large streamflow volumes, and flooding in June 2012 and 2014 was caused solely by rainfall, something never before recorded at the basin. Although the observed changes in climate and wetland drainage are substantial, it is unlikely that a single change can explain the dramatic shifts in the surface hydrology of the SCRB. Further investigation using process hydrology simulations is needed to help explain the observed regime changes.

Hydrokinetic tidal power is a novel and emergent technology undergoing continuous advancement with much of the progress focused on large utility scale projects. This resource is potentially underutilized because much of the coastal United States, despite having substantial tidal currents, do not have the deep and wide environments required by most of the developing turbine technology. This dissertation includes a detailed characterization of the tidal hydrodynamics for Rose Dhu Island, Georgia used for a tidal energy resource assessment as well as a general feasibility study for tidal estuaries with extensive wetlands. For predictions and evaluation of the estuarine hydrodynamics, data from an existing numerical model of the estuary encompassing the island is utilized. Field measurements in close proximity to the island are used to calibrate the model as well as characterize local hydrodynamic features. After the model calibration, the simulation data is used to evaluate the hydrodynamics. Wetland dominated estuaries commonly have a high degree of non-linear distortion which govern the relative durations and strengths of the tidal stages and thus the overall hydrodynamics and incoming hydrokinetic energy. The Ogeechee Estuary is characterized as ebb dominant with peak ebb and flood volume fluxes near high tide as a result of the increased storage capacity of the wetlands. Lowering the average wetland elevation in the model decreased ebb dominance and quickened the transition from flood to ebb tide. Increased domain friction in the model removed energy from the system and reduced ebb dominance. Enhanced model marsh friction reduced lateral flooding of the wetlands as well as ebb dominance. Localized measurements surrounding the island are analyzed to determine a location near the southwest coast of the island as a hydrokinetic energy hotspot. A kinematic and dynamic analysis is performed using channel transect measurements to identify key physical processes behind the hotspot formation. The hotspot forms due to sub-critical flow acceleration over a singular bump in the topography. High streamwise momentum is further concentrated at the hotspot due to secondary circulation cells across the channel. Flood tide circulation is characterized by two co-rotating cells induced by channel curvature and delineated by the bump. Ebb circulation consists of two counter-rotating cells from flow confluence of two upstream channels. Once the hydrodynamics are understood, the theoretical and technical resource assessment of the island is completed. A sensitivity analysis of hydrokinetic energy and tidal distortion is performed on synthetic data. For a principle constituent and its first harmonic, distortion greatly changes as does the distribution of velocities and energy as the relative phase varies. While the theoretical energy remains consistent, the technical energy can greatly vary. This effect is reduced with the addition semi-lunar variation. Using a simplified analytical method, the maximum average channel power is estimated as 8.80 MW. For the hotspot it is estimated that there is 30.3 MWh available to capture yearly with an average power of 3.46 kW for a turbine with an area of 10 square meters. For the same turbine area with conservative efficiencies, the hotspot could provide a yearly technical energy of 10.9 MWh with an average power of 1.25kW for the island. Due to the complex localized hydrodynamics, both the theoretical and technical resource varies greatly across and along the channel. These considerations are more pertinent when performing a hydrokinetic energy resource assessment in a marsh estuary than for large scale bay-ocean exchange environments, the present industry focus.

Η παρούσα διδακτορική διατριβή μελετά τις υδρογεωλογικές – υδροχημικές συνθήκες, που επικρατούν στην ευρύτερη περιοχή της αποξηραμένη λίμνης Μουριάς Ν. Ηλείας, με κύριο σκοπό τη δημιουργία μοντέλου ορθολογικής διαχείρισης των υπόγειων νερών. Το γεωλογικό υπόβαθρο της περιοχής έρευνας που περιλαμβάνει τμήμα της υδρολογικής λεκάνης του Αλφειού, τη λεκάνη της Σταφυλίας και τη μεσολεκανώδη των δύο υδρολογικών λεκανών περιοχή, δομούν οι ασβεστόλιθοι ηλικίας Παλαιοκαίνου της Ιόνιας ζώνης και οι εβαπορίτες. Τα μεταλπικά ιζήματα που διαδέχονται τους εβαπορίτες έχουν μεταβαλλόμενο πάχος, που φτάνει τα 2,5km και καλύπτουν σχεδόν ολόκληρη την περιοχή μελέτης. Τα ιζήματα αυτά αποτελούνται από αργίλους, μάργες, ιλυόλιθους και ψαμμίτες σε εναλλαγές. Τρεις κύριες διευθύνσεις ρηγμάτων δημιουργούν ένα πολύπλοκο καθεστώς διάρρηξης στην περιοχή της πόλης του Πύργου. Τα ρήγματα ΒΔ – ΝΑ διεύθυνσης απαντώνται στα νότια και ανατολικά της πόλης του Πύργου, στην περιοχή του Επιταλίου και του Πανόπουλου αντίστοιχα. Ρήγματα διεύθυνσης ΒΑ – ΝΔ απαντώνται βόρεια της πόλης του Πύργου, στην περιοχή του Βουνάργου. Ρήγματα διεύθυνσης Α – Δ απαντώνται στα ΝΑ της πόλης του Πύργου εκατέρωθεν του ποταμού Αλφειού. Η τεκτονική δραστηριότητα και η σεισμικότητα της περιοχής είναι ιδιαίτερα ενεργή μέχρι σήμερα και έχει παίξει καθοριστικό ρόλο στην μεταλπική ιζηματογένεση, στην διαμόρφωση της γεωμορφολογικής δομής, στην ανάπτυξη του υδρογραφικού δικτύου και στην διαμόρφωση των υδρογεωλογικών συνθηκών. Το υδρογραφικό δίκτυο της περιοχής χαρακτηρίζεται ως μέτρια ανεπτυγμένο, με το τεκτονικό καθεστώς της περιοχής να αποτελεί καθοριστικό παράγοντα στη διαμόρφωση και ανάπτυξη του υδρογραφικού δικτύου. Επίσης ένα σημαντικό χαρακτηριστικό γνώρισμα του υδρογραφικού δικτύου της περιοχής είναι η απουσία δέλτα στις εκβολές των ποταμών και των χειμάρρων. Το γεγονός αυτό οφείλεται κατά κύριο λόγο στην έντονη δράση των κυμάτων, καθώς και στις τεκτονικές κινήσεις ανύψωσης των ακτών. Η γεωμορφολογική ανάπτυξη της ευρύτερης περιοχής του Πύργου – Αρχαίας Ολυμπίας χαρακτηρίζεται από ήπιο ανάγλυφο με μεγάλη εξάπλωση της πεδινής ζώνης και ομαλή μετάβαση στην λοφώδη και ημιορεινή ζώνη. Προς τα βόρεια και ανατολικά, καθώς η επίδραση της τεκτονικής είναι εντονότερη, το υψόμετρο της περιοχής σταδιακά αυξάνει και φτάνει μέχρι τα +640m, ενώ το μέσο υψόμετρο είναι +92m. Το μέσο ετήσιο ύψος βροχόπτωσης για την περιοχή του Πύργου είναι 828mm και από την ανάλυση των βροχομετρικών δεδομένων για ολόκληρη την υδρολογική λεκάνη του Αλφειού, προέκυψε μια σχετικά έντονη πτωτική πορεία των ετησίων τιμών βροχόπτωσης κατά τα τελευταία 25 χρόνια και ειδικά η περίοδος 1984-1999 θεωρείται περίοδος ξηρασίας. Ο μέσος ετήσιος όγκος νερού από βροχόπτωση το χρονικό διάστημα 1975 – 2004, ανέρχεται σε 3.962,4x106m3, που αντιστοιχεί σε ένα μέσο ύψος 1.103,7 mm ατμοσφαιρικών κατακρημνισμάτων, κατανεμημένων σε όλη την υδρολογική λεκάνη του Αλφειού. Με βάση το ισοζύγιο κατά Thornthwaite – Mather, οι απώλειες λόγω εξατμισοδιαπνοής υπολογίζονται σε 1.497,05x106m3 νερού ανά έτος, ή 413 mm νερού κατανεμημένων σε όλη την επιφάνεια της περιοχής έρευνας. Η μέση ετήσια ποσότητα νερού που κατεισδύει ανέρχεται σε 1.104,09x106m3 νερού, κατανεμημένων σε όλη την επιφάνεια της περιοχής έρευνας, ή ποσοστό 35,29 % του ύψους βροχής. Από μετρήσεις παροχής στη θέση Φράγμα Φλόκα υπολογίσθηκε ότι ο μέσος ετήσιος όγκος νερού ανέρχεται σε 1.613,36x106 m3. Στην ευρύτερη περιοχή μελέτης αναπτύσσονται υδροφόρα στρώματα τόσο ελεύθερου χαρακτήρα, όσο και υπό πίεση, που ανήκουν στο σχηματισμό του Βουνάργου. Τα υδροφόρα στρώματα που διερευνήθηκαν εντοπίζονται στην πεδινή περιοχή του Πύργου, στην υπολεκάνη του Ενιπέα και στην περιοχή του Βουνάργου, που ανήκει στη λεκάνη της Σταφυλίας. Οι προσχωματικοί υδροφόροι της πεδινής περιοχής παρουσιάζουν τιμές των υδραυλικών ιδιοτήτων, που κρίνονται τυπικές για έναν ελεύθερο υδροφόρο. Οι υπό πίεση υδροφόροι ορίζοντες αναπτύσσονται σε βαθύτερα στρώματα στους ψαμμίτες του σχηματισμού του Βουνάργου και είναι υψηλής δυναμικότητας. Στην πεδινή ζώνη οι ψαμμίτες αυτοί απαντώνται σε βάθος μεγαλύτερο των 30m περίπου και οριοθετούνται από αργιλικά στρώματα. Οι συχνές εναλλαγές στρωμάτων άμμου και αργίλου κατά θέσεις, καθώς και η παρουσία πολυάριθμων ρηγμάτων στο σχηματισμό του Βουνάργου οδηγεί πολλές φορές σε πιθανή μίξη νερών από βαθύτερους υδροφόρους. Η τροφοδοσία του υδροφόρου αυτού γίνεται κυρίως μέσω κατείσδυσης του νερού των βροχοπτώσεων, καθώς και μέσω ρηγμάτων και διαρρήξεων. Από τη μελέτη της πιεζομετρίας της περιοχής του Πύργου διαπιστώνεται ότι ο ελεύθερος υδροφόρος ορίζοντας παρουσιάζει αρνητικές απόλυτες στάθμες στις παράκτιες περιοχές καθ’ όλη τη διάρκεια του υδρολογικού έτους. Αυτό οφείλεται κυρίως στη λειτουργία των αντλιοστασίων για την αποστράγγιση των επιφανειακών νερών της περιοχής, τα οποία στην παράκτια ζώνη αντλούν και μέρος των υπόγειων. Η αριθμητική προσομοίωση του ελεύθερου υδροφόρου ορίζοντα στην περιοχή του Πύργου έγινε με τη χρήση του λογισμικού Flowpath και έδωσε ικανοποιητικά αποτελέσματα όσον αφορά στην προσομοίωση της πιεζομετρικής επιφάνειας αλλά και στην επεξεργασία ενός αξιόπιστου υδρογεωλογικού ισοζυγίου. Σύμφωνα με αυτό, περίπου το 15% του νερού στον υδροφόρο προέρχεται από πλευρικές διηθήσεις του ποταμού Αλφειού, ενώ το υπόλοιπο 85% προέρχεται από την κατείσδυση του νερού των βροχοπτώσεων την χειμερινή περίοδο και των αρδεύσεων τη θερινή περίοδο. Τα αποστραγγιστικά κανάλια παίζουν πολύ σημαντικό ρόλο στην περιοχή, καθώς οδηγούν στα αντλιοστάσια και τελικά στη θάλασσα περίπου το 85% του νερού του υδροφόρου, με το υπόλοιπο 15% να εκφορτίζεται υπόγεια προς τη θάλασσα. Ακόμη το μοντέλο έδωσε τη δυνατότητα πρόβλεψης της συμπεριφοράς του υδροφόρου σε περίπτωση αλλαγής των υδρολογικών συνθηκών στην περιοχή. Στην περιοχή της Μουριάς, όπου τη θερινή περίοδο η τροφοδοσία του υδροφόρου είναι άμεσα συνδεδεμένη με τις αρδεύσεις, παρατηρήθηκε ότι ένας σταθερός όγκος νερού κατεισδύει στον υδροφόρο ακόμα και με μηδαμινές βροχοπτώσεις. Διερευνήθηκε καταρχήν το υποθετικό σενάριο της υψηλής βροχόπτωσης κατά τη χειμερινή περίοδο και προσδιορίστηκε το υδρογεωλογικό ισοζύγιο. Σύμφωνα με αυτό το 82% των εισροών στον υδροφόρο προέρχεται από την απευθείας κατείσδυση του νερού των βροχοπτώσεων και των αρδεύσεων, ενώ το υπόλοιπο 18% διηθείται πλευρικά από τον Αλφειό ποταμό. Το 13% περίπου εκρέει υπόγεια προς τη θάλασσα, ενώ το 87% οδηγείται προς τη θάλασσα μέσω των αντλιοστασίων. Ένα ακόμα υποθετικό σενάριο που διερευνήθηκε ήταν η προσομοίωση του ελεύθερου υδροφόρου ορίζοντα πριν την αποξήρανση της λίμνης Μουριάς τη δεκαετία του 1960. Από την εφαρμογή του μοντέλου και την προσομοίωση της λίμνης Μουριάς, αποδεικνύεται ο ρόλος των στραγγιστικών αντλιοστασίων και των αποστραγγιστικών καναλιών στη διαμόρφωση του υδραυλικού χαρακτήρα της περιοχής, καθώς στο παρελθόν και πριν την αποξήρανση της λίμνης Μουριάς, το υδραυλικό φορτίο ήταν υψηλότερο σε ολόκληρη την περιοχή κατά 2m περίπου. Ενδιαφέρον επίσης παρουσιάζει το γεγονός, ότι σύμφωνα με το υδρογεωλογικό ισοζύγιο οι πλευρικές διηθήσεις από τον ποταμό Αλφειό προς τον υδροφόρο ορίζοντα εμφανίζονται μειωμένες κατά 10% περίπου σε σχέση με την σημερινή κατάσταση. Αυτό αποδίδεται στο γεγονός ότι η παρουσία των στραγγιστικών αντλιοστασίων (και ειδικότερα αυτού που απέχει 500m από τον Αλφειό) δημιουργούν αναρρόφηση νερού από τον ποταμό ενισχύοντας έτσι την πλευρική διήθηση. Ακόμη παρατηρήθηκε ότι η κατανομή των πιεζομετρικών καμπύλων παρουσιάζεται περισσότερο ομοιόμορφη σε σχέση με τις σημερινές συνθήκες. Σε ορισμένες θέσεις στον ελεύθερο υδροφόρο ορίζοντα της περιοχής του Πύργου παρουσιάζονται φαινόμενα ιοντοανταλλαγής, λόγω της διείσδυσης του θαλασσινού νερού προς την ενδοχώρα. Οι θέσεις αυτές εντοπίστηκαν κυρίως σε μία ζώνη παράλληλη της ακτογραμμής, η οποία καταλαμβάνει το ανατολικό τμήμα της αποξηραμένης λίμνης Μουριάς και εκτείνεται έως τον ποταμό Αλφειό. Επίσης παρατηρήθηκε το φαινόμενο της αποδολομιτίωσης και της οξείδωσης του σιδηροπυρίτη, ενώ οι ανθρωπογενείς επιδράσεις αντανακλώνται από τις υψηλές συγκεντρώσεις κυρίως των ενώσεων του αζώτου. Τα φαινόμενα αυτά επιβεβαιώθηκαν και από την παραγοντική ανάλυση, η οποία πραγματοποιήθηκε για τα κύρια στοιχεία και τα ιχνοστοιχεία του ελεύθερου υδροφόρου ορίζοντα. Στη χημική σύσταση του νερού των αποστραγγιστικών καναλιών οι συγκεντρώσεις των στοιχείων είναι αυξημένες κυρίως στην παράκτια ζώνη, και αυτό μπορεί να οφείλεται τόσο σε επίδραση από το θαλασσινό νερό, όσο και σε ρύπανση από ανθρωπογενείς παράγοντες. Οι μέγιστες τιμές που λαμβάνουν τόσο τα κύρια στοιχεία, όσο και τα ιχνοστοιχεία καθιστούν τα επιφανειακά αυτά νερά ακατάλληλα για κάθε χρήση, καθώς στα κανάλια καταλήγουν συχνά οικιακά και βιομηχανικά απορρίμματα εμπλουτίζοντας το νερό σε βαρέα μέταλλα. Στα πλαίσια της παρούσας διατριβής η ερευνητική ομάδα του προγράμματος ΠΕΝΕΔ κατασκεύασε σε μία έκταση 5 στρεμμάτων στο ανατολικό άκρο της αποξηραμένης λίμνης Μουριάς μία πειραματική λίμνη. Το βρόχινο νερό που κατέκλυσε την εκσκαφή της νέας λίμνης, ήρθε σε επαφή με τα αργιλικά ιζήματα που κυριαρχούν στην περιοχή και μέσα σε μικρό χρονικό διάστημα το νερό απέκτησε υψηλές συγκεντρώσεις στοιχείων. Οι υψηλές συγκεντρώσεις σε σίδηρο και μαγγάνιο των δειγμάτων νερού του υπό πίεση υδροφόρου της περιοχής του Πύργου είναι ο κυριότερος λόγος για την ακαταλληλότητά τους. Η επικράτηση αναγωγικών συνθηκών σε μεγάλο τμήμα του υδροφόρου ευνοεί τις υψηλές συγκεντρώσεις των στοιχείων αυτών. Η υδροχημική έρευνα στα δείγματα νερού του υπό πίεση υδροφόρου ορίζοντα του σχηματισμού του Βουνάργου έδειξε ότι τα νερά αυτά έχουν γρήγορη ανανέωση σε σχέση με τον υπό πίεση υδροφόρο της περιοχής του Πύργου και η τροφοδοσία τους γίνεται από βόρειες και ανατολικές διευθύνσεις. Η παρουσία H2S σε συνδυασμό με τις αυξημένες συγκεντρώσεις NH4+ και βορίου οφείλονται στην πιθανή ανάμιξη του νερού με θερμομεταλλικά νερά, που βρίσκονται βαθύτερα και αναδύονται μέσω ρηγμάτων. Στην υδρολογική λεκάνη της Σταφυλίας και ειδικότερα κατά μήκος της ρηξιγενούς ζώνης Βουνάργου – Κατακόλου διαπιστώθηκε η ύπαρξη νερών με ιδιαίτερα υδροχημικά χαρακτηριστικά, όπως οι υψηλές συγκεντρώσεις νατρίου, η έκλυση μεθανίου, υδροθείου κ.ά. Οι υψηλές συγκεντρώσεις CO2 σε συνδυασμό με την ύπαρξη ραδονίου στα υπόγεια νερά θεωρείται ότι οφείλονται στην ύπαρξη θερμομεταλλικής υδροφορίας, η οποία εκδηλώνεται σε μία επιμήκη ζώνη παράλληλη στο ρήγμα του Βουνάργου. Οι θερμομεταλλικές εμφανίσεις της περιοχής πιθανά συνδέονται με την κατείσδυση μετεωρικού νερού σε μεγάλα βάθη μέσω μεγάλων τεκτονικών ασυνεχειών. Σε μεγάλα βάθη το νερό έρχεται σε επαφή με εβαπορίτες και εμπλουτίζεται με θειικά ιόντα, τα οποία λόγω του αναγωγικού περιβάλλοντος ανάγονται σε υδρόθειο. Η άνοδος του θερμομεταλλικού νερού προς την επιφάνεια γίνεται μέσω τεκτονικών ασυνεχειών. Στην πορεία του αναμιγνύεται με νερά υδροφόρων οριζόντων, που βρίσκονται σε μικρότερο βάθος με αποτέλεσμα η θερμοκρασία του να μειώνεται, προκαλώντας παράλληλα μεταβολή του υδροχημικού χαρακτήρα των υδροφόρων αυτών. Η εφαρμογή της μεθόδου DRASTIC στην περιοχή του Πύργου οδήγησε στην δημιουργία ενός μοντέλου τρωτότητας του ελεύθερου υδροφόρου ορίζοντα με βάση τους ρύπους που εισάγονται στην επιφάνεια του εδάφους. Η τροποποίηση της αρχικής μεθοδολογίας ως προς τις τιμές των παραμέτρων, αλλά και της βαρύτητας των συντελεστών, επέφερε ικανοποιητική συσχέτιση μεταξύ της ενδογενούς τρωτότητας και της συγκέντρωσης του ολικού αζώτου. / The present thesis deals with the hydrogeological – hydrochemical conditions that dominate in the wider area of the former Mouria Lake, in Ilia Prefecture, in order to develop a model for rational management and protection of aquifers. The bedrock in the research area, which comprises part of the hydrological basin of the Alfios River, the Staphylia Basin and the intrabasinal region, is formed of Paleocene limestone of the Ionian zone and the evaporites. The post-alpic sediments that overly the evaporites, have a varying depth that is up to 2.5km, covering almost the entire study area. These sediments consist mainly of clay, marl, siltstone and sandstone. Three major fault trends develop a complex fault system in the Pyrgos area. The NW – SE fault trends are in the south and east part of Pyrgos town, while the NE – SW trending faults occur in the area of Vounargo village. The E – W trending faults are found in the SE part of Pyrgos town, parallel to Alfios River valley. The tectonics and the seismicity of the study area is active until today and has played a prominent role in the post-alpidic sediments, as well as in the shaping of today’s relief, in the development of the drainage network and the local hydrogeological characteristics. The hydrographic network in the study area is relatively well developed, while active tectonics is the major factor in the development of the hydrographic network. Another basic characteristic of the hydrographic network is the absence of delta in the river estuaries. This is mainly due to the wave action, as well as to the tectonic uplift of the coastline. The geomorphological development of the entire area is characterized by a smooth relief. It is a flat to semi-mountainous region, with a mean altitude of +92 m, which diminishes gradually westwards. The mean annual precipitation in the Mouria area amounts to 828mm. From the precipitation data analysis for the whole Alfios Basin, a rather gentle declining trend of the mean annual values in the last 25 years, with a relatively more sharp decline in the period 1984-1999 can be observed. The mean annual volume of precipitation for the period 1975 – 2004 is 3.962,4x106m3 distributed in the whole Alfios basin. According to the Thornthwaite – Mather ‘s hydrological balance, 1.497,05x106m3 of water evapotranspirate annually, which equal to 413 mm distributed in the whole Alfios Basin. The average annual volume of water that infiltrates to the aquifers amounts to 1.104,09x106m3 for the Alfios Basin, which is 35.29 % of the rainwater. As derived from runoff measurements in Flokas Dam, 1.613,36x106 m3 of water annually, flows into the sea. In the broad study area several aquifers develop in different geological layers both unconfined and confined at greater depths in the Vounargo Formation. The aquifer layers studied are located in Pyrgos area, in the sub basin of Enipeas River (Alfios tributary) and in Staphylia Basin. The alluvial aquifers appearing in the lowland area, have typical hydraulic characteristics of unconfined aquifers. The confined aquifer bodies are developed in the deepest sandstone layers of the Vounargo Formation. In the lowland area these sandstones are found deeper than 30m intercalating with shales. The alterations of sand and clay is very common in many places and in addition to the presence of a number of faults in the Vounargo Formation, they result in water mixing from deeper aquifers to upper water bodies. The recharge of the confined aquifer is through infiltration of rainwater, as well as through faults and discontinuities that allow surface water to reach the aquifer bodies. From the study of the piezometrical maps in Pyrgos area, it is shown that the alluvial aquifer in the lowland area has a negative hydraulic gradient throughout the hydrological year. This is due to the use of pump stations that cause severe drawdown, especially in the coastal zone as the drainage channels connect to the aquifer at that area. The numerical simulation of the alluvial aquifer in Pyrgos area was done using Flowpath software. The results were very satisfying regarding both the simulation of the piezometrical surface and the reliable hydrogeological balance. According to this, 15% of the aquifer water derives from lateral leakage from Alfios River, while 85% derives from infiltration of the rainwater during the winter period and irrigation water during the summer period. The drainage channels play a very important role in the area as they lead 85% of the groundwater to the sea and the rest 15% is underground runoff towards the sea. Additionally, the prediction of the aquifer’s piezometrical surface and balance in case stresses change, was checked by the use of the Flowpath. In the study area the aquifer is constantly recharged throughout the year even during the summer due to the water use for irrigation. So the scenario that was checked, was that of heavy rainfall and the hydrological balance was checked for the new stress period. According to the results, 18% of the aquifer water derives from lateral leakage from Alfios River, while 82% derives from infiltration of the rainwater during the winter period and irrigation water during the summer period. Another hypothesis, is of simulating the aquifer before the drainage of the Mouria Lake that took place in 1960 ‘s. Results show that the role of drainage channels is significant for the study area as in the past decades before the drainage of the Mouria Lake the groundwater level was 2 meters higher. According to the hydrogeological balance, the lateral leakage from the Alfios River is decreased 10% in relation to the present situation. Ion–exchange phenomena are taking place in the alluvial aquifer of Pyrgos, due to seawater intrusion towards the inner land. This takes place especially in a zone parallel to the sea shore extending from the former Mouria Lake to Alfios River. Moreover, dedolomitization and pyrite oxidation are taking place in the aquifer, whereas high concentrations of ammonia is attributed to anthropogenic contamination. These phenomena were confirmed also by the factor analysis applied to the major and trace element contents. As regards the chemical composition of the drainage channels, the high concentrations of elements, especially in the coastal zone, are attributed not only to seawater intrusion but also to anthropogenic contamination. The maximum values of major and trace elements show that channel water is inappropriate for any use, as house and fabric waste usually are found in those channels thus enriching water with heavy metals. In the frame of the PENED project, the project team designed and constructed a lake in a 0.5-ha large area, in the eastern part of the drained Mouria lake. The rainwater that flooded the new lake became saline during its 3-month interaction with the clay sediments that dominate in the area. High concentrations of iron and manganese in water samples from the confined aquifer in the Pyrgos area are the main reason for their inappropriateness. The domination of reducing conditions in a big part of the aquifer favors the existence of those elements. The hydrochemical research in the samples of the confined aquifer in Vounargo Formation showed that there is a quick recharge in relation to the confined aquifer in Pyrgos area and their recharge is from the north and east part of the study area. The presence of H2S along with the high concentrations of NH4+ and B, are attributed to possible mixing with thermal waters that are found deeper and come upwards through faults. In the Staphylia Basin and especially along the Vounargo–Katakolo fault zone, the existence of waters with special characteristics was studied, like high sodium concentrations, methane release etc. High CO2 and Rn concentrations in groundwaters are attributed to the thermal waters and their existence near the Vounargo fault zone. The thermal waters in the area are possibly connected to the infiltration of meteoric water in great depths via large tectonic discontinuities. At great depths the water contacts the evaporites and enriches in sulfate ions that reduce to sulphuretted hydrogen, due to the reducing conditions. The uplift of the thermal water towards the surface is done through rock discontinuities, while it mixes with water bodies of upper layers, resulting in the decrease of its temperature, but at the same time causing changes in the hydrochemical type of the upper aquifers. The DRASTIC method was applied in the Pyrgos area and led to the development of the intrinsic vulnerability model of the alluvial aquifer, based on contaminants injected to the land surface. The modification of the initial methodology as regards the parameter values and the weight factors resulted in satisfying correlation between the intrinsic vulnerability and the concentration of total nitrogen.

In arid lands, wetland loss is the result not only of the scarcity of water itself, but of the management of water to maximize off-stream uses. Declaring a wetland as a protected natural area is not enough when its water supply is not protected as well. In a fully-diverted, over-allocated, drought-prone Colorado River ecosystem, its delta has no instream flows allocated. Water use efficiency (WUE) is touted as the panacea for water shortages and lack of instream flows. I evaluated the relationships between water use in the Mexicali Irrigation District and the water supply for the Colorado River delta wetlands. The survey applied to 521 farmers complemented the GIS analysis to create a spatial distribution of agronomic and socio-economic factors influencing farmers’ options to improve WUE in irrigation. Mexicali farmers apply 10,496 m³/ha/yr; 4% higher than the legal allotment. Still, 28% of the district’s soils are salt-affected (ECe > 8dS/m), 19% are sodic (ESP > 50%), and 39% of the salt load in irrigation water accumulates in the soils. Thus, Mexicali farmers apply more water than plants need in order to maintain the sustainability of their soils. From an agronomic perspective, increasing WUE is feasible in 80% of the valley. However, high costs and lack of technical knowledge limit farmers’ options to either continue using as much water as they do now or rent/sell their water rights to larger farming operations or urban developments. Mexicali’s agriculture provides 87 Mm³ of water to the delta marshes, and seepage from unlined canals and subsurface flows generated by irrigation contribute to sustain riparian areas. Agricultural “inefficiencies” become the main source of water for wetlands when flows are fully diverted. The Irrigation District 014 is an integral part of the delta ecosystem; this is a required change in the agriculture-wetland paradigm. The restoration of arid and over-allocated rivers requires the integration of irrigation practices and WUE with the allocation of water for instream flows. The restoration of wetlands of international watersheds like the Colorado River requires the bi-national collaboration beyond memorandums of understanding between the countries; treaties where environmental flows are actually allocated will better serve shared ecosystems.