No abstract

Phosphorus is a water pollutant of concern around the world as it limits the productivity of most freshwater systems which can undergo eutrophication under high phosphorus inputs. The importance of treating stormwater as part of an integrated phosphorus pollution management plan is now recognized. Bioretention systems are urban stormwater best management practices (BMPs) that rely on terrestrial ecosystem functions to retain storm flows and reduce pollutant loads. Bioretention has shown great potential for stormwater quantity and quality control. However, phosphorus removal has been inconsistent in bioretention systems, with phosphorus leaching observed in some systems. Numerical models can be used to predict the performance of bioretention systems under various conditions and loadings. The aim of this paper is to identify and characterize bioretention phosphorus cycling processes, with a particular focus on process modelling. Both soluble and particulate phosphorus forms are expected in significant proportions in bioretention system inflows. Sorption mechanisms are expected to dominate soluble phosphorus cycling, while particulate phosphorus transport occurs mainly through sedimentation. Vegetative uptake, mineralization, and immobilization are also known to play a role in the cycling of phosphorus; however, data is lacking to assess their importance. There is a need for simple mathematical equations to represent dissolution and precipitation reactions in bioretention systems. More research is also needed to characterize the rates of colloidal capture and mobilization within soils. Finally, approaches used to model phosphorus transport in systems similar to bioretention are not applicable to bioretention system modelling. This reinforces the need for the development of a bioretention phosphorus transport model.

No abstract

No abstract

(NSF and IES 2018) describe reproducibility as a continuum (Fig. 1). The goal is to push work up the continuum to make data, models, code, directions, and other digital artifacts used in the research available for others to reuse (availability). Then, use shared artifacts to exactly reproduce published results (reproducibility, sometimes called bit or computational reproducibility). Finally, use artifacts with existing and new data sets to replicate findings across sites or domains (replicability). For example, the Journal of Water Resources Planning and Management policy to specify the availability of data, models, and code (Rosenberg and Watkins 2018) primarily targets availability in the reproducibility continuum. This Fig. 1. Reproducibility is a continuum.

Bioretention systems are designed to treat stormwater and provide attenuated drainage between storms. Bioretention has shown great potential at reducing the volume and improving the quality of stormwater. This study introduces the bioretention hydrologic model (BHM), a one-dimensional model that simulates the hydrologic response of a bioretention system over the duration of a storm event. BHM is based on the RECARGA model, but has been adapted for improved accuracy and integration of pollutant transport models. BHM contains four completely-mixed layers and accounts for evapotranspiration, overflow, exfiltration to native soils and underdrain discharge. Model results were evaluated against field data collected over 10 storm events. Simulated flows were particularly sensitive to antecedent water content and drainage parameters of bioretention soils, which were calibrated through an optimisation algorithm. Temporal disparity was observed between simulated and measured flows, which was attributed to preferential flow paths formed within the soil matrix of the field system. Modelling results suggest that soil water storage is the most important short-term hydrologic process in bioretention, with exfiltration having the potential to be significant in native soils with sufficient permeability.

No abstract

PVC pipe wall samples were acquired from a full-scale drinking water distribution laboratory using 3D printed coupons. Brightfield microscopy and imaging processing were used to investigate iron oxide particles deposited on samples surface.