As the numbers of installed greenroofs continue to grow internationally, designing greenroof growing media to reduce the amount of nutrients in the stormwater runoff is becoming essential. Biochar, a carbon-net-negative soil amendment, has been promoted for its ability to retain nutrients in soils and increase soil fertility. This study evaluated the effect on water quality of greenroof runoff after adding biochar to a typical extensive greenroof soil. Prototype greenroof trays with and without 7% biochar (by weight) were planted with sedum or ryegrass, with barren soil trays for controls. The greenroof trays were subjected to two sequential 2.9 in/hr rainfall events using a rainfall simulator. Runoff from the rainfall events was collected and evaluated for total nitrogen, total phosphorus, nitrate, phosphate, total organic carbon, and inorganic carbon. Greenroof trays containing biochar showed lower quantities of nutrients in the stormwater runoff compared to trays without biochar. Biochar-amended soil with and without plants showed a 3- to 25-fold decrease in release of nitrate and total nitrogen concentrations, as well as a decrease in phosphate and total phosphorus concentrations release into the rainfall runoff. Phosphorus results from trays planted with sedum indicate that sedum interacted with both soils to cause a decrease of phosphorus in the greenroof runoff. In correlation with a visual effect in turbidity, biochar-amended soil showed a reduction of total organic carbon in the runoff by a factor of 3 to 4 for all soil and plant trays. Inorganic carbon was similar for all tests showing that inorganic carbon neither reacted with, nor was retained by, biochar in the soil. The addition of biochar to greenroof soil is an effective way to retain nutrients in a greenroof soil, reduce future fertilizer demands, and improve the water quality of the stormwater runoff by reducing nitrogen, phosphorus, and total organic carbon concentrations in the runoff water.

Urbanization, often characterized by high impervious surface area, can result in excessive inputs of fine sediments into urban streams. Excessive fine sediments can blanket the stream bed filling the interstitial space in the substratum, which may have adverse effects on stream biota. A field survey was conducted in Oregon urban and non-urban basins to investigate the relationship between fine sediments and stream macroinvertebrates. Physical, chemical, and biological data were collected from 59 stream sites in two urban and two rural streams. The stream sites fulfilled a continuous sediment gradient, which ranged from a low of 2% of fine sediment in the substrate to a high of 64% with an average of 22%. The % fines, in Clear Creek (rural basin) was significantly lower than in the urban basins (Johnson Creek and Tryon Creek) (p=0.005). Johnson Creek (mean=23%) had approximately three times more fine sediment than Clear Creek (mean=7%), while Tryon Creek (mean=32%) had nearly five times as much fine sediment as Clear Creek. EPT taxa richness was significantly higher in both rural streams than in both urban streams (p0.05). For example, regression analysis of EPT taxa richness vs. % fine sediments displayed a coefficient of determination (r2) value of 0.2. Other macro invertebrates metrics displayed similar patterns. The lack of significant correlations may be due to the cumulative effect of basin-wide "historical land use past". Past land use activity may have resulted in long-term reductions of sensitive taxa in the basin taxa pool and efforts to improve local habitats may not be quickly colonized by pollution sensitive taxa. Long-term degradation to the urban streams resulted in a relatively homogenous assemblage of macro invertebrates, which may have confounded the quantitative relationship between sediments and macroinvertebrates. This study suggests there is a clear difference between urban and non-urban streams in terms of macro invertebrates, which may be likely due to sediments, but the quantitative relationship between fine sediments and macro invertebrates is weak.

Thesis (PhD)--Stellenbosch University, 2003. / ENGLISH ABSTRACT: The Plankenbrug River runs past the dense settlement of Kayamandi, on the outskirts of Stellenbosch. This site was chosen to study the impact of water pollution from formal and informal urban developments on water quality and associated health factors. Aims of the study: (1) To determine some basic epidemiological characteristics of the exposed population of Kayamandi, their sanitation problems and reasons for poor hygiene; (2) To determine the microbiological and chemical pollution load patterns in the Plankenbrug River over time; (3) To investigate the spectrum of organisms present in the river (other than the indicator E. coli) and their epidemiological implications for health; (4) To establish the possible presence of organisms resistant to chlorine or to antibiotics in the river below Kayamandi as indicators of environmental hazard. Methods: During the period 5 May 1998 to 10 February 2003 microbiological and chemical analyses have been carried out every 6 weeks on water samples obtained at various points along the Plankenbrug River. Two large surveys (n=2196 persons and n=3568 persons) of the community of Kayamandi have been undertaken and door-to-door education campaigns were carried out with the aid of trained community health workers. Results: Below Kayamandi the river contains dangerously high levels of faecal contamination and it constitutes a health hazard to all persons coming into contact with the water. Up to 13 million Escherichia coli per 100 ml water was recorded (cut-off level as indicator of human safety is 1000 organisms per 100 ml water). Not all the faecal contamination originated from Kayamandi. Substantial amounts of faecal contamination sporadically entered the river at different points below Kayamandi. The pollution load resulting from these intrusions were sometimes larger than that contributed by the whole of Kayamandi. Water samples below Kayamandi were screened to ascertain what other pathogens were present. Amongst the organisms were 0 haemolytic Streptococcus Group A and B, Mycobacterium intracellulare, Staphylococcus spp, Klebsiella spp., Pseudomonas spp. and many others. The list of pathogens found had such serious implications that a confidential health warning was sent out to health care centres and other affected organisations in the area. |3 haemolytic Streptococcus Group A has never before been reported as isolated in viable form from free-flowing natural waters. Signs of increased resistance to chorine were found in organisms isolated from the river water. There were also organisms showing signs of resistance to commonly used antibiotics. The E. coli organisms that survived various levels of chlorine treatment also showed increased resistance to amoxycillin when compared to untreated E. coli organisms sampled from the Plankenbrug River. During the community phase of the project in Kayamandi a reduction in the pollution levels occurred over the summers of 2000 and 2001 (note that "improved" does not yet mean "safe" by any means). This can be ascribed to the multi-pronged approach of the project. Attention was given to service and repair of sanitation facilities, a strong accent on door-todoor community education about better sanitation behaviour, creation of a central reporting point for blockages and breakages, and training of artisans (plumbers, bricklayers, etc) from the community to help with upkeep. The community showed encouraging signs of wanting better sanitation education. The improvement in pollution levels is however in danger of reverting back to the previous dangerous situation if better support and co-operation cannot be obtained from the relevant authorities. There were 16.9% of households who reported one or more cases of diarrhoea during the survey period (5 weeks) - a very high prevalence seeing that the survey was carried out during a wet and cold winter period. Conclusions: Active planning and other steps to cope with the sewage intrusions into the river should be instituted without delay. The water quality of the Plankenbrug River downstream from Kayamandi is extremely poor. The water constitutes a serious health hazard and a threat to downstream economic activities. The settlement of Kayamandi demonstrated that education, when coupled with maintenance and repairs of existing toilet facilities, can bring about a reduction in pollution loads, but that this should be an ongoing process and not be reduced to sporadic attempts. / AFRIKAANSE OPSOMMING: Die Plankenbrug Rivier vloei verby die digbewoonde nedersetting van Kayamandi aan die buitewyke van Stellenbosch. Hierdie plek is gekies as studie-area om die impak te bestudeer van waterbesoedeling wat van formele en informele dorpsontwikkeling afkomstig is, asook die geassosieerde gesondheidsfaktore. Doel van die studie: (1) Om sommige basiese epidemiologiese eienskappe van die blootgestelde populasie, hulle sanitasieprobleme en redes vir die swak higiene te bepaal; (2) Om die mikrobiologiese en chemiese besoedelingspatrone in die Plankenbrug Rivier oor tyd te bepaal; (3) Om die spektrum van organismes teenwoordig in die rivier (anders as E. coli) te bepaal asook hulle epidemiologiese implikasies op gesondheid; (4) Om vas te stel, as indikatore van omgewingsgevaar, of daar moontlik organismes teenwoordig is wat weerstandig is teen chloriene en antibiotika in die rivier onder Kayamandi. Metodes: Gedurende die afgelope vier jaar is mikrobiologiese en chemiese ontledings elke 6 weke uitgevoer van watermonsters wat van verskeie punte op die Palnkenbrug Rivier verkry is. Twee groot opnames is in die gemeenskap van Kayamandi ondemeem (n=2196 persone en n=3568 persone) en deur-tot-deur opvoedingsveldtogte is uitgevoer met die hulp van plaaslik opgeleide gemeenskapsgesondheidswerkers. Resultate: Onder Kayamandi bevat die rivier gevaarlike vlakke van fekale besoedeling en dit hou gesondheidsgevare in vir alle persone war daarmee in aanraking kom. Op tot 13 miljoen Escherichia coli per 100 ml water is genoteer (boonste grens van veiligheid vir die mens is 1000 organismes per 100 ml water). Nie al die fekale kontaminasie is afkomstig van Kayamandi nie. Substansiele hoeveelhede kontaminasie dring die rivier binne op verskillende punte ver onder Kayamandi. Hierdie besoedelingslading is soms groter as wat van die hele Kayamandi afkomstig is. Watermonsters geneem onder Kayamandi is ondersoek om vas te stel watter ander siekteveroorsakende organismes ook teenwoordig was. Onder die organismes gevind was (3 hemolitiese Streptococcus Groep A en B, Mycobacterium intracellulare, Staphylococcus spp., Klebsiella spp., Pseudomonas spp. en baie ander. Die lys van patogene wat gevind is, het sulke emstige implikasies dat 'n vertroulike gesondheidswaarskuwing uitgestuur is na gesondheidsdienspunte en ander geaffekteerde organisasies in die gebied. (3 hemolitiese Streptococcus Groep B is nog nie vantevore aangemeld as lewensvatbaar geisoleer uit vryvloeiende natuurlike waters nie. Tekens is gevind dat daar organismes in die rivier voorkom wat weerstandig is teen chloorbehandeling en ook teen algemeen gebruikte antibiotika. Die E. coli organisme wat verskillende konsentrasies van chloorbehandeling oorleeef het, het ook verhoogde weerstand teen amoksisilien getoon wanneer hulle vergelyk was met onbehandelde E. coli organisme wat van die Plankenbrug Rivier gemonster was. Gedurende die gemeenskapsfase van die projek is daar 'n verlaging van besoedelingsvlakke in die rivier gevind gedurende die somers van 2000 en 2001 (let op dat "verbetering" hier nog glad nie "veilig" beteken nie). Dit kan toegeskryf word aan die veelvlakkige benadering wat die projek gevolg het. Aandag is geskenk aan diens en herstel van sanitasiegeriewe met 'n sterk klem op deur-tot-deur opvoedingsveldtogte met die oog op beter sanitasiegedrag, skepping van 'n sentrale aanmeldpunt vir blokkasies en brekasies, en opleiding van ambagslui (loodgieters, messelaars, ens) uit die gemeenskap om te help met onderhoud. Die gemeenskap het bemoedigende tekens getoon dat hulle beter sanitasie opvoeding verlang. Die verbetering in die besoedelingsvlakke in die rivier loop egter gevaar om terug te val na die vorige gevaarlike vlakke as daar nie beter ondersteuning en samewerking van die onderhawige owerhede verkry kan word nie. Daar was 16.9% van huishoudings wat een of meer gevalle van diarree aangemeld het gedurende die 5 weke van die opnameperiode - 'n baie hoe prevalensie siende dat die opname uitgevoer was gedurende 'n nat en koue winterperiode. Gevolgtrekkings: Aktiewe beplanning en ander stappe om die riool-indringing in die rivier die hoof te bied is gebiedend noodsaaklik en behoort sonder versuim ingestel te word. Die waterkwaliteit van die Plankenbrug Rivier stroomaf van Kayamandi is baie swak. Die water hou emstige gesondheidsgevare in en is ook 'n bedreiging vir die ekonomiese aktiwiteite stroomaf. Die nedersetting van Kayamandi demonstreer ook dat opvoeding, wanneer gekoppel aan onderhoud en herstel van bestaande toiletgeriewe in verlaging teweeg kan bring van besoedelingsvlakke, maar dat dit 'n voortgesette program moet wees en nie net sporadiese pogings nie.

Bibliography :leaves 158-171. A monitoring program, funded by the South Australian government (through the former MFP Development Corporation), was established to monitor the quality and quantity of storm water entering and leaving the wetland. This study formed part of the funded program. Simple regression models were developed; and will assist in the monitoring of performance of the wetland to alleviate the pollutant load into the Barker Inlet.