Stormwater ponds design to mitigate the negative impacts of runoff from impervious surfaces in urban areas have become common landscape features as they are required by state and local environmental regulations. While some have hypothesized that stormwater ponds may provide habitat for wildlife, few studies have systematically investigated turtle use of stormwater ponds. To investigate stormwater pond use by turtles in western Virginia, I used records of permitted stormwater management structures in the Town of Christiansburg and City of Blacksburg, Virginia, and a stratified random sample design based on hydrology to select 60 (of 324 above ground structures) for sampling of turtle assemblages. I used a combination of visual and trapping surveys to characterize turtle assemblages. I also surveyed design and management variables to identify those conditions that promote use of stormwater ponds by turtles. Visual encounter surveys involving eight or more visits conducted in June and July when air temperatures were between 20oC and 27oC produced high cumulative rates of detection and high detection probabilities during individual surveys, respectively. I found eight taxa utilizing stormwater ponds including two relatively abundant native taxa, the snapping turtle (Chelydra serpentina) and the eastern painted turtle (Chrysemys picta picta), and one non-native taxa, the red-eared slider (Trychemys scripta elegans). The occurrence of turtles was associated with larger ponds with permanent or near permanent hydrology and limited emergent vegetation cover that were located on streams and surrounded by patches of trees and turfgrass cover. These conditions are characteristics of the habitats selected by the native species found in this study, but also indicative of conditions humans may choose when releasing unwanted pet turtles. Therefore, the occurrence of native and non-native taxa may be associated with park-like conditions, but for different reasons, warranting future assessment and monitoring of turtle populations and potential genetic introgression between native and non-native taxa. / Master of Science / Stormwater ponds design to mitigate the negative impacts of runoff from polluted surfaces have become common landscape features in urban areas. While there is evidence that stormwater ponds provide habitat for fish, birds, amphibians, insects, and macroinvertebrates, not many studies have addressed their use by reptiles, particularly turtles. In this study, I investigated turtle use of stormwater ponds in Christiansburg and Blacksburg, Virginia. I conducted visual and trapping surveys of turtles and estimates of habitat conditions during the spring and summer of 2022 and 2023. I found that stormwater retention ponds were providing habitat for eight taxa of turtles, three of which appeared to be successfully nesting near ponds. Two taxa occurred at 18 or more ponds and are widespread in the eastern United States. Three taxa were not native to my study area in western Virginia and appear to have been introduced to stormwater ponds by humans, probably via release of unwanted pets. Turtle taxa were most abundant at larger ponds, with open water areas, located on streams, and surrounded by patches of trees and turfgrass. These are the conditions preferred by the native species found in my study; they may also be the conditions perceived by humans to be good places to release unwanted pets. Therefore, stormwater ponds may be providing habitat for native species, but also creating communities of native and non-native taxa that could have ramifications for the genetic integrity of native taxa.

The City of Denton, located in a semi-arid region of Texas, has over 200 manmade ponds within its city limits. Many of these ponds, located in densely populated areas, are engineered to control storm water runoff. There is a general lack of recognition of the value these waters contribute to regional biodiversity and as greenspaces. This study, conducted in Denton, is monitoring habitat variables and macroinvertebrate diversity in a series of ponds selected to represent a gradient of urban influences. The objective of this study is to identify the variables associated with the highest diversity. Using drone imagery and a meter square box sampler, the quantitative approach allowed for delineation of three habitat types and area. The macroinvertebrates where identified to the genus level which allowed for higher resolution and resulted in stronger comparisons of the communities and conditions of the ponds. Taxa richness was positively correlated to pond size and trees along shoreline and negatively associated with average depth. Overall, submerged vegetation supported highest diversity and abundance, especially genera of Chironomidae (Diptera). Conductivity was associated with urban influences and the most urban influenced pond had the lowest taxa richness, but also reduced habitat area. Results of this study conclude that these stormwater ponds benefit to the ecology of the city and provide beautiful, green spaces. If managed correctly, these systems can be incorporated into sustainable development in the future of the City of Denton.

Este trabalho comparou oito lagoas de estabilização da região Noroeste do Estado de São Paulo, que tratam esgotos predominantemente sanitários de Coroados, Lourdes, Planalto, Zacarias, Alto Alegre, Pongaí, Irapuã e Adolfo, cidades pequenas, com no máximo 5500 habitantes (1700 ligações), onde os quatro primeiros sistemas são compostos apenas por lagoas facultativas primárias e os quatro últimos por lagoas anaeróbias e lagoas facultativas secundárias. Vinte e cinco variáveis físicas, químicas e biológicas foram analisadas em amostras compostas coletadas entre 24/05/2000 e 03/10/2000. A análise da batimetria efetuada fornece indicações de prazos para a remoção do lodo do fundo das lagoas. As taxas de acúmulo de lodo médias obtidas para as lagoas anaeróbias e facultativas primárias foram de 0,07 e 0,14 m3/hab.ano, respectivamente. O pH do efluente das lagoas anaeróbias e das facultativas foi em média 6,6 e 7,4. Nas lagoas anaeróbias observou-se alta remoção de sólidos suspensos e de Demanda Bioquímica de Oxigênio (DBO) com eficiência geral média de 64% e 61% respectivamente. Os sistemas não atenderam plenamente à legislação no tocante a eficiência de remoção de DBO de 80%, porém o valor médio encontrado para os oito sistemas foi de 78%, bastante próximo do exigido. Sugere-se para a região, para eficiência de remoção de DBO de 80%, lagoas anaeróbias com tempo de detenção de 5 dias e para as lagoas facultativas primárias e secundárias tempos de detenção de 25 e 15 dias respectivamente, e taxas de aplicação superficial de 140 e 130 kg DBO/ha.dia, respectivamente. Não foi atingido o limite máximo de 1000 coliformes fecais por 100 ml, obtendo-se média geral de remoção de 97,40% inferindo-se que há necessidade de um processo de tratamento complementar para a remoção de microrganismos. Não observou-se correlação entre eficiência do sistema e relação comprimento/largura das lagoas. Constatou-se maus odores mesmo na ausência de concentrações detectáveis de sulfeto. A remoção média geral de amônio (NH4+), nitrogênio total, fosfato total dissolvido e fósforo total foi de 31%, 12%, 24% e 27% respectivamente nos sistemas estudados. / The present work compared the performance of eight stabilization ponds in the Northwest region of São Paulo state, that treat predominantly the domestic sewage from eight small cities with a maximum of 5000 inhabitants (1700 links): Coroados, Lourdes, Planalto, Zacarias, Alto Alegre, Pongaí, Trapuã and Adolfo. The first four systems are made of four primary facultative ponds and the last four by anaerobic ponds and secondary facultative ponds. A total of twenty-five chemical, physical and biological variables were analyzed in integrated samples collected between 24/05/2000 and 03/10/2000. The bathymetric analysis performed has indicated deadlines for sludge removal from the stabilization pond bottom. Mean sludge accumulation rates o btained for anaerobic and primary facultative ponds were 0.07 and 0.14 m3/inhabt.year, respectively. Effluents from anaerobic and facultative ponds had a mean pH of 6.6 and 7.4. In anaerobic ponds a righ rate of suspended solids removal was found and the Biochemical Oxygen Demand (BOD) had an overall general efficiency of 64% and 61%, respectively. The systems did not completely attend the present legislation in respect to a BOD removal of 80%, as required, however the mean value for the eight systems monitored was 78%, very close to the established limit. It is therefore suggested that for this region, in order to attain the removal efficiency of 80% anaerobic ponds should have a residence time of 5 days and the primary and secondary facultative ones should have residence times of 25 and 15 days respectively, coupled to loading rates of 140 and 170 Kg BOD/ha.day respectively. Also, the maximum limit of 1000 fecal coliforms per 100 ml was not reached, and in general there was a mean removal efficiency of 97.40%, indicating that an additional treatment process needs to be implemented for a successful removal of coliforms. No correlation was found between the removal efficiency and morphometry (length/weight) pond characteristics. Bad smell was present even in the absence of detectable amounts of sulfide. The mean efficiency for the removal of ammonium (NH4+), total nitrogen, total dissolved phosphorus and total phosphorus were 31%, 12%, 24%, and 27% respectively, among the systems studied.

Este trabalho comparou oito lagoas de estabilização da região Noroeste do Estado de São Paulo, que tratam esgotos predominantemente sanitários de Coroados, Lourdes, Planalto, Zacarias, Alto Alegre, Pongaí, Irapuã e Adolfo, cidades pequenas, com no máximo 5500 habitantes (1700 ligações), onde os quatro primeiros sistemas são compostos apenas por lagoas facultativas primárias e os quatro últimos por lagoas anaeróbias e lagoas facultativas secundárias. Vinte e cinco variáveis físicas, químicas e biológicas foram analisadas em amostras compostas coletadas entre 24/05/2000 e 03/10/2000. A análise da batimetria efetuada fornece indicações de prazos para a remoção do lodo do fundo das lagoas. As taxas de acúmulo de lodo médias obtidas para as lagoas anaeróbias e facultativas primárias foram de 0,07 e 0,14 m3/hab.ano, respectivamente. O pH do efluente das lagoas anaeróbias e das facultativas foi em média 6,6 e 7,4. Nas lagoas anaeróbias observou-se alta remoção de sólidos suspensos e de Demanda Bioquímica de Oxigênio (DBO) com eficiência geral média de 64% e 61% respectivamente. Os sistemas não atenderam plenamente à legislação no tocante a eficiência de remoção de DBO de 80%, porém o valor médio encontrado para os oito sistemas foi de 78%, bastante próximo do exigido. Sugere-se para a região, para eficiência de remoção de DBO de 80%, lagoas anaeróbias com tempo de detenção de 5 dias e para as lagoas facultativas primárias e secundárias tempos de detenção de 25 e 15 dias respectivamente, e taxas de aplicação superficial de 140 e 130 kg DBO/ha.dia, respectivamente. Não foi atingido o limite máximo de 1000 coliformes fecais por 100 ml, obtendo-se média geral de remoção de 97,40% inferindo-se que há necessidade de um processo de tratamento complementar para a remoção de microrganismos. Não observou-se correlação entre eficiência do sistema e relação comprimento/largura das lagoas. Constatou-se maus odores mesmo na ausência de concentrações detectáveis de sulfeto. A remoção média geral de amônio (NH4+), nitrogênio total, fosfato total dissolvido e fósforo total foi de 31%, 12%, 24% e 27% respectivamente nos sistemas estudados. / The present work compared the performance of eight stabilization ponds in the Northwest region of São Paulo state, that treat predominantly the domestic sewage from eight small cities with a maximum of 5000 inhabitants (1700 links): Coroados, Lourdes, Planalto, Zacarias, Alto Alegre, Pongaí, Trapuã and Adolfo. The first four systems are made of four primary facultative ponds and the last four by anaerobic ponds and secondary facultative ponds. A total of twenty-five chemical, physical and biological variables were analyzed in integrated samples collected between 24/05/2000 and 03/10/2000. The bathymetric analysis performed has indicated deadlines for sludge removal from the stabilization pond bottom. Mean sludge accumulation rates o btained for anaerobic and primary facultative ponds were 0.07 and 0.14 m3/inhabt.year, respectively. Effluents from anaerobic and facultative ponds had a mean pH of 6.6 and 7.4. In anaerobic ponds a righ rate of suspended solids removal was found and the Biochemical Oxygen Demand (BOD) had an overall general efficiency of 64% and 61%, respectively. The systems did not completely attend the present legislation in respect to a BOD removal of 80%, as required, however the mean value for the eight systems monitored was 78%, very close to the established limit. It is therefore suggested that for this region, in order to attain the removal efficiency of 80% anaerobic ponds should have a residence time of 5 days and the primary and secondary facultative ones should have residence times of 25 and 15 days respectively, coupled to loading rates of 140 and 170 Kg BOD/ha.day respectively. Also, the maximum limit of 1000 fecal coliforms per 100 ml was not reached, and in general there was a mean removal efficiency of 97.40%, indicating that an additional treatment process needs to be implemented for a successful removal of coliforms. No correlation was found between the removal efficiency and morphometry (length/weight) pond characteristics. Bad smell was present even in the absence of detectable amounts of sulfide. The mean efficiency for the removal of ammonium (NH4+), total nitrogen, total dissolved phosphorus and total phosphorus were 31%, 12%, 24%, and 27% respectively, among the systems studied.

published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

Lack of sufficient water for irrigation is a major problem in and around the valleys surrounding the town of Aiquile, Cochabamba Bolivia. In addition, much of the region is undergoing desertification compounded by drought, deforestation, bad traditional agricultural practices, over grazing and a "torrential" rainfall pattern leading to severe soil erosion and low agricultural production. Between 1992 and 1994, the author constructed a network of 24 small, mostly rainfed farm ponds to increase agricultural production and alleviate soil erosion and land-use problems by improving cover conditions. A 5-year post-impoundment analysis was carried out in 1998. The analysis examined current pond conditions, design criteria, irrigation water / crop production increases and the alleviation of land-use problems. Current pond conditions fell into four distinct categories with only 25 percent of the ponds being deemed as "functioning well." The project increased irrigation in the region and improved cover conditions in 66 percent of the pond sites.

[Truncated abstract. Formulae and special characters in this field can only be approximated. See PDF version for accurate reproduction.] Solar salt producers use solar energy to evaporate seawater as it flows through a series of ponds. The Shark Bay Salt solar ponds, at Useless Inlet in Western Australia, vary in salinity from that of seawater to four times seawater, over the pond sequence. Water column photosynthesis and biomass decreased markedly with increasing salinity along the pond sequence, while benthic productivity increased as cyanobacterial mats developed. Correspondingly, net productivity shifted from autotrophy to heterotrophy in the water column and from heterotrophy to autotrophy in the benthos. Both shifts occurred at intermediate salinity in the pond sequence, where there was low production in both the water column and benthos. Within individual ponds, productivity, algal biomass and physico-chemical conditions were relatively constant over the year of study. Transitions between benthic and planktonic production along the pond sequence were driven mostly by direct responses to salinity stress, as well as the formation of a gypsum crust on the pond floors at higher salinity (>120 g kg-1). This transition is similar to that which occurs in saline lakes undergoing anthropogenic salinisation and identifies critical salinities for the restoration of these lakes.

Thesis (MEng)--Stellenbosch University, 2002. / ENGLISH ABSTRACT: In the present study, research was conducted to determine the feasibility of water energy storage through which the output of heated air by an upward facing solar air heater could be prolonged. Following a systematic approach, a number of experimental test swere initially performed on an upward facing solar air heater in order to obtain a benchmark that could be used to evaluate the influence of water storage during the day-time performance of a solar air heater. As expected, an increase in the air mass flow rate not only led to an increase in the collector efficiency but also to a decrease in the temperature gain across the collector. In addition, a number of day- and night-time experiments were executed on a plastic covered water tank in order to evaluate it's ability to store and discharge thermal energy. Results clearly indicated that the plastic covered water tank was both an ideal collector and storage medium of solar energy. Experimental results also revealed that the plastic covered water tank was an ideal source of thermal energy for a solar air heater during night-time operation. Subsequently, both day- and night-time experiments were performed on an upward facing solar air heater in which plastic covered water tanks were installed. Day-time experimental results revealed that the modified solar air heater still had the same collector efficiency tendency, as observed in the initial solar air heater experiments, but that the water energy storage led to a dramatic decrease in the absorber plate temperature and in the corresponding temperature gain experienced across the collector. In contrast, the night-time operation results clearly indicated that the water energy storage was not only able to prolong the output of heated air by the solar air heater, but was further able to increase the air temperature by between 7.5 and 1.5 °e, depending on the air mass flow rate. It was furthermore shown in the study that available theory is able to accurately predict the performance of an upward facing solar air heater, either with or without water energy storage, as long as the equations are employed within their range of validity / AFRIKAANSE OPSOMMING:In die hierdie studie is daar ondersoek ingestel na die lewensvatbaarhied van son-energiestoring in water ten einde die tydperk van lugverhitting deur 'n son-Iugverwarmer te verleng. 'n Sistematiese prasedure is gevolg waardeur daar aanvanklik 'n aantal eksperimente op 'n son-Iugverwarmer uitgevoer is am sodoende die eienskappe van so 'n lugverhiUingstelsel, sander energie storing, te vekry. Die resultate het getoon dat 'n toename in die massavloei tempo van die lug lei tot 'n toename in die kollektor effektiwiteit van die stelsel, maar terselfdetyd lei tot 'n afname in die temperatuur styging in die kollektor. Met die eienskappe van die lugverwarmingstelsel bekend, is daar voorts 'n aantal dag- en nag-eksperimente uitgevoer op 'n plastiek bedekte watertenk am die storing en vryselling van termiese energie deur die watertenk te kwantifiseer. Die resultate het daarap gedui dat die plastiek bedekte watertenk nie net beide 'n goeie kollektor en stoor medium vir son-energie is nie, maar oak dat dit 'n ideale bran van termiese energie vir 'n lugverwarmingstelsel tydens die nag is. Met inagname van die vorige resultate, is daar dan 'n aantal plastiek bedekte watertenks in die apparaat geinstalleer, en 'n aantal dag- en nag-eksperimente is uitgevoer. Die dageksperimente het getoon dat die die nuwe lugverwarmer met water energie storing dieselfde eienskappe toon ten opsigte van die kollektor effektiwiteit as die oorspronkilke son-Iugverwarmer. Tog, as gevolg van die laer absoberende plaat temperature was die temperatuur toename in die kollektor heelwat laer. In kontras hiermee dui die nagresultate aan dat die plastiek bedekte watertenks nie net die vermoe het am die tydperk van lugverwarming te verleng nie, maar oak dat die lug tempertuur, afhangende van die massavloei tempo van die lug, met tussen 1.5 en 7.5 °C verhoog kan word. Die studie het laastens oak getoon dat dit moontlik is am met behulp van beskikbare teorie die temperatuur toename in die kollektor van 'n son-Iugverwarmer met of sander water energie storing, akkuraat te voorspel, mits die vergelykings binne hul geldige gebiede gebruik word.

The methods developed in this study are for the purpose of assessing the potential of small-scale surface water impoundments, or ponds, to provide local water supplies and detain sediments from going to the main reservoir on the Wadi Zarat watershed, northwestern Libya. The Wadi Zarat watershed has an area of about 213 km2 and receives a mean annual rainfall of 270 mm. A stochastic rainfall model was developed to simulate rainfall. This model was then combined with a deterministic model to estimate runoff. A modification of the Soil Conservation Service runoff model was utilized. The results of the rainfall and runoff models were then used to estimate sediment yield using the Modified Universal Soil Loss Equation. Parameters for these models were obtained from data and studies on the Wadi Zarat watershed. A combined model that incorporates the rainfall, runoff, and sediment yield models along with equations to route the runoff and sediment through the ponds was developed. A FORTRAN V computer program was written to perform the tasks of the combined model. The computer program was designed to give the results for a set of pond performance criteria. These criteria were developed to provide an easy and comprehensive tool to compare the interaction of the pond with the rainfall, runoff, and sediment coming from a given watershed. To have a representative range of watershed-pond combination, a total of 8 watersheds, 8 ponds, and 2 seepage rates were examined. The models used gave satisfactory results and indicated a great potential for future use in other parts of the study area region and possibly other regions of the country. The results of the main model were used to develop relationships and guidelines that can be used by the planner to decide on a particular watershed-pond combination on the Wadi Zarat watershed. Equations to predict the optimum pond volume on a particular watershed size and characteristics were also developed. The study showed a great potential for small-scale surface water ponds on the Wadi Zarat watershed. The methods developed in this study are encouraging and open the door for future use in other parts of the country.

2009 metais devyniolikoje (su padaliniais dvidešimt viename) Lietuvos žuvininkystės ūkių buvo vykdomi gulbių nebylių sankaupų gausos, formavimosi sezoninės dinamikos ir pasiskirstymo ypatumų tyrimai. Tyrimai užpildo eilę spragų ankstesniuose tyrimuose apie gulbių nebylių sankaupų formavimąsi žuvų tvenkiniuose. Sankaupų formavimosi laikotarpiu žuvų auginimo tvenkiniais naudojasi apie tris tūkstančius neperinčių gulbių nebylių. Paukščiai čia apsistoja sezoninių migracijų metu. Taip pat čia susirenka šertis nesiveisiantys individai. Gulbių buvimo žuvininkystės ūkių tvenkiniuose trukmę apsprendžia tvenkinių pripildymo (balandžio mėn.) ir nuleidimo (intensyviausiai rugsėjo antroje - spalio pirmoje pusėje) laikotarpiai. Sankaupos gausiausios pavasario pabaigoje - vasaros pradžioje, visų pirma birželio mėnesį, tačiau jų dydis atskiruose ūkiuose ženkliai svyruoja ir gali piką pasiekti ir kitais sezono laikotarpiais, ypač rudeniop. Stabiliai pagrindiniu, sankaupų dydį konkrečiuose žuvų ūkiuose apsprendžiančiu, veiksniu yra bendras tvenkinių, kuriuose buvo beriami žuvų pašarai, plotas. Ūkiuose (jų grupėse), kuriuose šio faktoriaus skaitinė reikšmė didelė, gulbių nebylių sankaupos taip pat didelės ir atvirkščiai. Tačiau atsitiktinė natūralių buveinių su gausiomis gulbių nebylių sankaupomis (pavyzdžiui Kuršių Marių) kaimynystė (geografinis faktorius), gali nusverti anksčiau minėto faktoriaus poveikį. Gulbės sankaupose naudoja didžiąją dalį konkretaus, ūkio tvenkinių (paprastai 50-70 %) –... [toliau žr. visą tekstą] / In 2009, research was carried out on abundance of mute swan flocks, its formation, seasonal dynamics and distribution characteristics in nineteen (with branches in twenty-one) fish farms in Lithuania. This research fills-in a number of gaps of previous studies on mute swan flocks formation in fish farm ponds. Around three thousand non breeding mute swans are using fish farming ponds during flock’s formation season. Birds stay here during seasonal migrations. Also non breeding swans gather here to moult. The duration of stay of swans in fish farm ponds is determined by the time of filling up (in April) and draining (most intensive in the second half of September and in the first half of October) of ponds. The most numerous flocks are at late spring - early summer, particularly in June, but the size of individual flocks vary considerably and may reach peak during other periods of the season, especially in autumn. The most stable factor determining size of the specific flock in fish farm ponds is area of the pond where fish are fed. Flocks are more numerous in farms (or groups of farms) in which value of this factor is higher and vice versa. However, random natural dwellings of mute swan flocks with large populations (for example neighborhood of Kuršių Marios – geographical factor) may outweigh the above factor’s impact on mute swans flock size in fish ponds. Flocks of mute swans cluster during the mobilization period and use most part of the fish farm pond (usually 50-70%) –... [to full text]