Runoff Retention Research Articles

Methane and ammonia emissions from a beef feedlot in western Canada for a twelve-day period in the fall

Commercial feedlot operations are becoming a mainstay in the Canadian beef industry. These large operations that typically raise thousands of animals at a time represent a large localized source of methane (CH4) and of atmospheric pollutants such as ammonia (NH3) and particulate matter. An inverse dispersion model was utilized to calculate CH4 and NH3 emissions from a commercial cattle feedlot and an adjacent runoff retention pond. The feedlot measurements were collected within the interior of the feedlot enabling a near continuous emissions record over the 12 d of the study period. Average daily emission estimates of CH4 and NH3 were 323 and 318 g animal-1 d-1, respectively. The CH4 emissions represent 4% of the gross energy intake (GEI) and NH3 emissions represent 72% of the total N intake. Emissions from the runoff retention pond associated directly with the feedlot operation were approximately 2.7 and 2% of the daily average feedlot emissions of CH4 and NH3, respectively. Key words: Methane, ammonia, inverse dispersion, ruminant livestock, trace gas emissions

Green roofs are not created equal: the hydrologic and thermal performance of six different extensive green roofs and reflective and non-reflective roofs in a sub-tropical climate

Green roofs have the potential to retain stormwater on the roof surface and lower the thermal loading on buildings. Because of this, the greatest environmental benefits from green roofs might be achieved in subtropical climates characterized by high temperatures and intense rain events. There is, however, little research to support this. In a replicated study in Texas, we compared the performance of six different extensive green roof designs vegetated with native species, to non-reflective (black) roofs, and reflective (white) roofs. Preliminary hydrologic and thermal profile data indicated not only differences between green and non-vegetated roofs, but also among green roof designs. Maximum green roof temperatures were cooler than conventional roofs by 38°C at the roof membrane and 18°C inside air temperature, with little variation among green roofs. Maximum run-off retention was 88% and 44% for medium and large rain events but some green roof types showed very limited retention characteristics. These data demonstrate indicate that: 1. Green roofs can greatly affect the roof temperature profile—cooling surface layers and internal space on warm days. 2. Green roofs can retain significant amounts of rainfall, this is dependent on the size of the rain event and design and can fail if not designed correctly. We suggest that as green roofs vary so much in their design and performance, they must be designed according to specific goals rather than relying on assumed intrinsic attributes.

Partitioning and granulometric distribution of metal leachate from urban traffic dry deposition particulate matter subject to acidic rainfall and runoff retention

Vehicular transportation coupled with urban hydrology is a significant source as well as vector of particulate matter (PM) and particulate-bound metal inventories in urban systems. This study examines the granulometric distribution of metals from dry deposition PM generated from 17 dryfall periods and equilibrium metal partitioning with runoff PM distribution from eight rainfall-runoff events at an urban inter-state watershed in Baton Rouge, LA. Dry deposition PM is a coarse non-uniform gradation with a d 50m = 304 μm and a peak surface area at 106 μm. Results indicate acid rain is not a significant metal contributor to runoff but is capable of leaching metals from PM to runoff. Retained runoff partitioning resulted in particulate-bound predominance for As, Cd, Cr, Cu, Pb, and Zn while Ca and Mg remained predominately dissolved. The finer PM fraction (<75 μm) generates the highest metal concentrations and the highest metal mass is associated with the coarser fraction (>75 μm). This coarse fraction is also the most labile when exposed to acidic rainfall; generating up to 90% of the total metal mass leached from the entire PM gradation. Comparing dry deposition and runoff PM of equal mass and size gradation, retained runoff PM is enriched with metals (except Pb). Results indicate the labile coarse fraction of dry deposition PM can be a significant source of metal leaching while runoff PM (mobilized dry deposition PM) stored in a BMP can be metal-enriched with the potential for re-leaching or scour.

Paired catchment storm event monitoring: Assessing the performance of a bioretention system (rain garden)

Treating urban runoff at its source offers to protect receiving waters by modifying flow characteristics and improving water quality. This paper presents the findings for a paired catchment storm event monitoring program undertaken at a residential development, the Lynbrook Estate, Victoria, Australia. The monitoring program compares catchment runoff characteristics between a landscaped bioretention system and a conventional concrete pipe system located in adjacent urbanised subcatchments. Results indicate that the extent to which bioretention systems function as hydrological buffers depends on their design attributes, in-situ geology, antecedent moisture conditions at inflow and storm magnitude. Reductions in total runoff volume, duration and peak flows discharged from the bioretention system compared to the piped system were observed. Small, frequently-occurring runoff events are completely retained by the system. Pollutant loads are reduced by a combination of catchment runoff retention and physical and/or chemical treatment processes, with the former being the dominant process for nutrients and the latter being dominant for suspended solids. Analysis of pollutant load reduction for the 10 events showed gross pollutant load was reduced by 100%, suspended sediment by 68%, total phosphorus by 60% and total nitrogen by 57%.

Biodiversity and ecosystem function in constructed ecosystems.

Abstract Constructed ecosystems are engineered to perform functions, such as bioremediation of contaminants, and are increasingly viewed as green alternatives to conventional technologies. Augmenting biodiversity of managed systems such as agroecosystems has been shown to improve yields and other functions such as nutrient uptake, but manipulation of organismal diversity linked to the functioning of constructed ecosystems is an emerging field that has not been reviewed. Here, we summarize current understandings of the relationships between biodiversity and the functions (services) of constructed ecosystems such as green roofs, sewage treatment wetlands and bioreactors, by reviewing theoretical expectations and experimental results. There are several ways in which increased plant species diversity is expected to improve functioning on green roofs. A positive effect of functional composition on water runoff retention has been demonstrated in one system. In wastewater treatment wetland systems, there are a handful of studies showing positive relationships between species diversity and nutrient uptake, but many showing no effect of species diversity. Studies on bioreactors and biofilms suggest that functional redundancy in microbial communities is a consequence of high biodiversity and can promote temporal stability in system performance. The inevitability of variable environmental conditions suggests that the insurance derived from biodiversity is likely important in most constructed ecosystems, but more experimental manipulations of biodiversity are necessary to test whether ecosystem functions can be optimized or stabilized in any system.

Tracing sources of summer streamflow in boreal headwaters using isotopic signatures and water geochemical components

Summary Content of 18O, 2H, 3H and geochemical components in rainfall, stream water, peat water and bedrock groundwater in four headwater catchments were compared to reveal differences in sources of runoff and hydrological vulnerability to tunnel drainage during summer. Water previously stored within the catchments was the predominant component of streamflow during small and moderate events. The proportion of event water increased at high discharge in autumn. Neither the isotopic nor the hydrochemical composition of stream water indicated any considerable contribution from old bedrock groundwater. Stream water hydrochemistry revealed clear influence of soil water pathways. The differences in land cover could be seen in water quality and runoff generation. Water storage and mixing in lakes and lowland wetlands reduced fluctuations in runoff and water quality. Runoff retention and the solute trapping effect in peatlands were most efficient in flat areas near the catchment outlet. In lowflow periods fluxes from hillslopes were of minor importance compared to discharges from wetland water storage. Water delivery from hillslopes with thin till cover (

Incorporation of Seasonal Nitrogen Dynamics within a Long-Term Acidification Model

This paper describes an application of the long termdynamic model, MAGIC, on a monthly timestep, enablingincorporation of the seasonal dynamics associated with abroad understanding of the ecosystem N cycle. The modelhas been applied to the Dargall Lane catchment in theGalloway region of Scotland where marked seasonal Ndynamics are apparent. Mean monthly proportions ofrainfall, runoff, deposition fluxes and net retention ofN are utilised to drive the model on a monthly timestep.Calibration of the model has successfully reproduced thepresent day observed seasonal variation in streamNO3 and ANC. Prediction of recovery at the siteunder the second sulphur protocol indicates that,although mean annual ANC increases, mean monthly ANC doesnot rise above zero for all months of the year until2010.

Figtree Place: a case study in water sensitive urban development (WSUD)

Figtree Place is a water sensitive urban redevelopment consisting of 27 residential units located in Hamilton, an inner suburb of Newcastle, NSW, Australia. The site uses rainwater tanks, infiltration trenches and a central basin where cleansed stormwater enters the unconfined aquifer for water retention and retrieval. A two-year monitoring programme for roofwater, raintanks, hot water systems and first flush pits has commenced with samples taken from these sources tested for compliance with the Australian Drinking Water Guidelines (1996). Total water saving of around 60% has been shown to be feasible as well as almost complete storm runoff retention.

218 Dissipation of Isoxaben in Simulated Gravel-based Nursery Runoff Retention Basins

Recent research indicated that the herbicide simazine dissipated quickly in gravel-based subsurface-flow constructed wetlands. This indicates that retention areas at nurseries may be developed to facilitate pesticide remediation and reduce offsite movement. A site to simulate runoff retention areas at a containerized nursery was established with troughs containing pea gravel and controls containing no gravel in an open field. Irrigation water was applied daily to replace half of the capacity of the trough, simulating daily irrigation and runoff at a nursery. A study was conducted to determine the effects of this system on isoxaben (a pre-emergent herbicide) concentrations in the water leaving the troughs and the change in microbial organisms associated with the gravel. Initially, 19 L of a dilute isoxaben solution (1.3 μg/L) was added to each tank. Drainage was collected and assayed for isoxaben concentration over a 40-day period. Isoxaben was detected in troughs containing gravel through 14 days while isoxaben was detected in troughs containing no gravel through only 4 days. Microbial analysis of the gravel showed a variety of microorganisms initially, but, by day 14, Pseudomonas spp. became the dominant genus present. Preliminary analysis revealed that the isoxaben binds to the gravel, and is then desorbed over time. Further investigations will include the abilites of Pseudomonas and other isolated organisms to metabolize isoxaben as the sole carbon-source in the laboratory.

Distribution, Ecology and Rarity of the Nationally Vulnerable Species Pultenaea selaginoides (Fabaceae)

Pultenaea selaginoides Hook.f. (Fabaceae) is a Tasmanian endemic shrub classified as nationally vulnerable. Only four populations of P. selaginoides totalling fewer than 1000 individuals are known to be extant, and one of these populations consists of only six individuals. The habitat of P. selaginoides is restricted to sites in flood-prone, riparian areas or coastal ridgelines subject to cloud-lie and runoff retention. However, there appears to be unoccupied habitat available. Pultenaea selaginoides can resprout or coppice after disturbance or regenerate from the soil stored seed bank. Most populations are producing seed, and large quantities may be produced. Germination of the seed can be induced by short-term temperatures of 60–100°C. Only the largest population is formally reserved, but all sites should be managed for the perpetuation of P. selaginoides. Because of the narrowness of its distribution, its low total population size, its innate seed dormancy, the ageing of most of the populations, and the uncertaintpy about the precise causes of its rarity, P. selaginoides should continue to be regarded as vulnerable to extinction.

Effects of Furrow Dikes on Water Conservation and Dryland Crop Yields

AbstractEliminating or reducing storm runoff in the Southern Great Plains can increase soil‐water storage, decrease erosion, and increase crop yields. The primary objectives of this study were (i) to examine the potential of furrow dikes as a conservation practice to retain runoff and increase crop yields, and (ii) to examine the effects of furrow diking on sorghum [Sorghum bicolor (L.) Moench] and sunflower (Helianthus annuus L.) production. Analyses of 28 yr of runoff records show furrow diking has the potential to retain 25 to 30 mm of runoff annually. The maximum annual runoff retention by diking observed during the 14 crop years of research (three separate experiments conducted between 1980 and 1985) was 111 mm. The maximum increase in sorghum yield measured as a result of diking was 2.46 Mg/ha. Conditions responsible for maximum yield responses of sorghum to diking were: (i) annual cropping, (ii) large rainfall/runoff events occurring prior to or early in the growing season, and (iii) limited growing season precipitation. Diking increased annual cropped sorghum yields on graded and contour furrow treatments by 49 and 14%, respectively, whereas water use efficiencies were increased by 25 and 16%. Yields and water use efficiencies from diked treatments on graded and contour furrows were as great as yields and water use efficiencies from a leveled minibench treatment, indicating that from a crop production standpoint, furrow diking was as effective as land leveling in retaining runoff and increasing crop yields. Sunflower yields were increased significantly by diking during 1 yr out of 3 when sunflower was grown after 76 weeks of fallow, whereas sorghum yields were not affected by diking after fallow. Decreasing row spacing from 1.0 to 0.75 m resulted in a significant increase in the 3‐yr avg yield of sorghum and sunflower of 1.0 and 0.14 Mg/ha, respectively, when grown after fallow, indicating that considerable opportunity for improving summer crop production may exist simply by changing to a narrow row spacing. A regression equation relating runoff from graded furrows to runoff from contour flat‐tilled graded terraces showed increased runoff from graded furrows, particularly from small storms.

An Evaluation Technique for Ground Water Quality Beneath Urban Runoff Retention and Percolation Basins

AbstractA subsurface water (vadose zone or ground water) extractor is described. Construction materials were Teflon and a porous ceramic suction cup. The unique features are: •Check valves are not needed. •Complete retention of water sample in a 1.8L capacity reservoir, even if vacuum is lost or when the reservoir is pressurized to transfer sample to ground surface and the collection bottle. •The extractor can usually be retrieved if the access well and well head as described are used. The ceramic cup can then be replaced if necessary and the extractor reused at another site. The water extractor is not suitable for obtaining samples for analysis of highly volatile pollutants.Up to four of these water extractors were used to monitor the quality of percolating urban runoff water and top of the ground water table (20 to 30m) beneath retention/recharge basins. The presence of water in the basins requires constructing a sealed borehole annular space, a watertight well head, and seal around the Teflon access tubes to the extractor at a control box containing the valves in the access tubes.

Predicting the Quality of Cattle Feedlot Runoff and Holding Pond Contents

ABSTRACT T is important to be able to predict the quality as well as the quantity of both feedlot runoff and retention basin contents if the wastewater is to be effectively utiliz-ed and if the pollution potential of various runoff control systems are to be evaluated. A procedure was devised to predict the quantity and quality of cattle feedlot runoff entering a runoff holding pond whenever precipitation occurs in excess of the sur-face holding capacity of the lot or whenever accumulated snow would melt. These predictions are based upon size and location of the feedlot, previous weather conditions, and daily climatic data. Runoff retention basin liquid content and quality are predicted on a daily basis which considers inputs and outputs as well as chemical and biological changes which are occurring on a continuous basis. The quality parameters which are predicted on a daily basis include: chemical oxygen demand (COD), total nitrogen (N), ammonia nitrogen (NH3-N), total phosphorous (P), total solids (TS), fixed dissolved solids (FDS), total coliforms (TC), fecal coliforms (FC) and fecal streptococcus (FS). A cattle feedlot in Illinois was sampled intensively to adjust the various coefficients of the predictive tool.

Animal Waste Management: State-of-the-Art

A detailed review of animal waste management literature references and current practices is presented with special emphasis on waste production characteristics, feedlot runoff, regulatory considerations, odor control, treatment methods, engineered systems and controls, animal waste utilization and economic considerations. Special attention is directed to engineering techniques which can be employed for cost-effective waste management. Basic design principles and performance criteria required for routine design of runoff retention facilities and pretreatment unit processes for either waste conservation or degradation prior to terminal land application set the basis for this in-depth review.

Rainfall Use Efficiency for Dryland Barley with Three Crop and Water Management Systems

AbstractThree crop and water management systems for barley (Hordeum vulgare L.) were compared in a winter rainfall climate on Hanford sandy loam. These systems were (i) annual corpping with runoff retention, (ii) a fallow‐crop sequence with runoff retention, and (iii) induced runoff on one‐half the area for concentration and annual cropping on the remaining half. Land slope was 2–3% and runoff was retained with dikes at 7.6‐m intervals in the first two systems. Over a 3‐year period average grain yields were 1.58, 2.04, and 2.29 ton/ha with rainfall use efficiencies of 41, 29, and 31 kg/ha‐cm for annual cropping, fallow‐crop, and induced runoff concentration systems, respectively. The additional soil water in downslope areas of the annual and fallow‐crop systems and in areas receiving induced runoff was reflected in increased barley kernels per head and greater kernel weight. Holding runoff on the land and cropping annually increased rainfall use efficiency 42% over both that obtained where runoff occurred in the annual cropping system and that obtained for the entire plot area in the fallow‐crop system. The efficiency of fallow for storing water in the soil was 16.7%.