Darko Joksimovic

Modeling low impact development potential with hydrological response units

Evaluations of benefits of implementing low impact development (LID) stormwater management techniques can extend up to a watershed scale. This presents a challenge for representing them in watershed models, since they are typically orders of magnitude smaller in size. This paper presents an approach that is focused on trying to evaluate the benefits of implementing LIDs on a lot level. The methodology uses the concept of urban hydrological response Unit and results in developing and applying performance curves that are a function of lot properties to estimate the potential benefit of large-scale LID implementation. Lot properties are determined using a municipal geographic information system database and processed to determine groups of lots with similar properties. A representative lot from each group is modeled over a typical rainfall year using USEPA Stormwater Management Model to develop performance functions that relate the lot properties and the change in annual runoff volume and corresponding phosphorus loading with different LIDs implemented. The results of applying performance functions on all urban areas provide the potential locations, benefit and cost of implementation of all LID techniques, guiding future decisions for LID implementation by watershed area municipalities.

The Perceptions of Stakeholders in Low Impact Development Planning

As part of measures to mitigate the impact of contaminants on Lake Simcoe, a project is being carried out by the Lake Simcoe Region Conservation Authority (LSR…

The use of WorldView-2 satellite imagery to model urban drainage system with low impact development (LID) Techniques

Within a wide range of best management practices for stormwater management in urban areas, there has been an increasing interest in source control measures. Source controls such as low-impact development (LID) techniques are potentially attractive as retrofit options for older developed areas that lack available land to implement conventional measures such as stormwater management ponds. Hence, distributed urban drainage models requiring detailed representation of developed drainage areas should be developed to accurately estimate the benefits that LIDs may provide. This study (1) presents a two-stage classification process on a high-resolution WorldView-2 image, and (2) demonstrates how to use the extracted land cover information in the subsequent hydrologic modelling and assessment of different LIDs’ performance. The proposed two-stage classification method achieved an overall accuracy of 80.6%, whereas a traditional pixel-based achieved 68.4% in classifying the same urban area into six land cover classes. From the classification results, the hydrologic properties of micro-subcatchments were imported in the United States Environmental Protection Agency Storm Water Management Model to assess the performance of LIDs. A reduction of run-off volume 18.2% and 37.1% was found with the implementation of porous pavement and bioretention, respectively, in a typical low-rise residential area located in the city of San Clemente, California, US. The study demonstrates the use of high-resolution remote sensing image to aid in evaluating LID retrofit options, and thus benefits in situations where detailed drainage area information is not available.

Probabilistic spill occurrence simulation for chemical spills management.

Inland chemical spills pose a great threat to water quality in worldwide area. A sophisticated probabilistic spill-event model that characterizes temporal and spatial randomness and quantifies statistical uncertainty due to limited spill data is a major component in spill management and associated decision making. This paper presents a MATLAB-based Monte Carlo simulation (MMCS) model for simulating the probabilistic quantifiable occurrences of inland chemical spills by time, magnitude, and location based on North America Industry Classification System codes. The models aleatory and epistemic uncertainties were quantified through integrated bootstrap resampling technique. Benzene spills in the St. Clair River area of concern were used as a case to demonstrate the model by simulating spill occurrences, occurrence time, and mass expected for a 10-year period. Uncertainty analysis indicates that simulated spill characteristics can be described by lognormal distributions with positive skewness. The simulated spill time series will enable a quantitative risk analysis for water quality impairments due to the spills. The MMCS model can also help governments to evaluate their priority list of spilled chemicals.

A USEPA SWMM Integrated Tool for Determining the Suspended Solids Reduction Performance of Bioretention Cells

A numerical tool was developed to calculate the stormwater runoff total suspended solids (TSS) removal efficiency of bioretention cells to assist engineers in …

A Right-of-Way Stormwater Low Impact Development Practice

Road right-of-way can provide a good retrofit opportunity to implement stormwater low impact development (LID) technologies. In Canada and the northern United …

Stormwater Exfiltration System for Road Retrofit

Road retrofit such as sewer replacement or road re-construction in existing urbanized area can provide a good opportunity to implement stormwater low impact development (LID) technologies. In Canada and northern USA, stormwater management should focus not only in summer and fall but also winter and spring. A stormwater exfiltration system was designed to manage stormwater over four seasons by retrofitting roads with two 200 mm (8 inches) perforated pipes with end capped below a storm sewer system. The design concept is to direct road runoff up to 13 mm of rainfall to these two perforated pipes with end capped and fill the void space of the sewer trench for exfiltration to the surround soil at all times (i.e. including snowmelt and winter rainfall). Two and a half kilometer of this exfiltration system was constructed in the City of Toronto and found (by monitoring) to be able to control rainfall up to 24 mm without overflowing to the storm sewer above. This paper presents the planning and design criteria, costs, construction and maintenance, and performance evaluation.

Hierarchical Optimization of Integrated Water Reuse Schemes

With up to 40% of the world’s population in over 80 countries and regions experiencing water stress, water reuse has emerged as a genuine and reliable alternat…

Evaluation of low impact development stormwater technologies and water reuse options for the lake Simcoe Regions.

In support of the efforts of the Lake Simcoe Region Conservation Authority (LSRCA) to meet its Vision for the Restoration and Protection of Lake Simcoe and its Watershed, Ryerson University conducted a study to evaluate the suitability and effect of implementation of non-conventional wastewater and stormwater control technologies, including low impact development technologies (LID) and water reuse options, within the pre-defined uncontrolled study area where conventional stormwater management practices were not feasible. The aims of the study project were to: identify opportunities for implementation of these technologies, quantify at a planning level the benefits that could be provided in terms of reduced nutrient loadings to Lake Simcoe, and ultimately provide guidance to municipalities within the watershed. Phase I compiled all the existing data and information, summarized the previous studies and projects that had been carried out to date deemed relevant to the project, and carried out a geographic information system analysis (GIS) of the opportunities for implementation of LID (based on suitability criteria such as land use and physical site requirements). Phase II carried out a more detailed study of the usage of LID identified in Phase 1 as being potentially suitable, evaluated the best combinations of LID (and their placement), quantified preliminary costs of their implementation and pollution reduction benefits such as annual nutrient loading reduction, and examined the opportunities for reclamation of wastewater and stormwater in the study area. Additionally, the effects of future development and climatic changes on the overall efficiency of promising solutions were evaluated. The modeling of the pollution reduction benefits was based on the development of hydrologic unit response functions (URF) for different land uses and LID combinations and the aggregation of these URF over the study area using GIS. The study findings indicate that the implementation of the feasible LID such as bioretention cell, rainwater harvesting, greenroof, and downspout disconnection could potentially reduce the nutrient loading from the uncontrolled study area by about 10 to 20%.

Model Calibration of a Large Urban Sewer System using Radar Precipitation Information

This chapter describes the development and calibration of an XP SWMM Project Model of the City of Ottawa’s major interceptor and collector sewers. The Project …