Great investment is made in the design and installation of stormwater control measures (SCMs). Substantial research investment, too, is made to optimise the performance of SCMs. However, once installed, SCMs often suffer from lack of maintenance or even outright neglect. Key maintenance needs for wet ponds, constructed stormwater wetlands, bioretention, infiltration practices, permeable pavement, swales, and rainwater harvesting systems are reviewed with many tasks, such as the cleaning of pre-treatment areas and the preservation of infiltration surfaces, being common maintenance themes among SCMs. Consequences of lacking maintenance are illustrated (mainly insufficient function or failure). Probable reasons for neglect include insufficient communication, unclear responsibilities, lack of knowledge, financial barriers, and decentralised measures. In future designs and research, maintenance (and lack thereof) should be considered. Assessing the performance of SCMs conservatively and including safety factors may prevent consequences of under-maintenance; and requiring regular inspection may help to enforce sufficient maintenance.

The effect of clogging on the long-term infiltration capacity and porosity of two 18- and 24-year-old porous asphalts was examined by using replicate double-ring infiltrometer tests and analyzing asphalt core samples. Tests were carried out to see if high pressure washing and vacuum cleaning could restore the hydraulic performance. The infiltration capacity of the porous asphalts decreased substantially, primarily due to surficial clogging (0.50±0.26 in Luleå, Sweden, and 0.22±0.12 in Haparanda, Sweden, compared to initially >290 mm min−1). In Luleå, washing and vacuum cleaning could partially restore the infiltration capacity (3.48±3.00 mm min−1), but in Haparanda, no effect was measured. The porosity was constantly between 16 and 18%. The difference of the long-term behavior and effect of cleaning in Luleå and Haparanda is primarily attributable to different street maintenance, age, and winter maintenance (application of fine gravel and/or sand). Although the infiltration capacity in Luleå was...

Permeable pavements allow stormwater to pass through the pavement surface, filtering out sediment and debris; over time, regular preventative maintenance will be needed to maintain the pavement surface infiltration rate (IR). IR testing is commonly used to determine maintenance needs and frequencies. ASTM standard methods may be used to measure permeable pavement IR; however, these tests can take hours to complete and require infiltrometers not readily available to maintenance contractors. A simple infiltration test (SIT) has been devised which (1) is conducted using easily acquired materials, (2) has a larger surface area (i.e., more representative of average pavement conditions), and (3) requires, on average, 72% less time to conduct than the ASTM test. ASTM and SIT methods were compared by conducting a total of 873 IR tests at the same locations on 12 permeable pavements in North Carolina, Ohio, and Sweden. Results showed that (1) a segmented linear relationship related SIT and ASTM-measured IR...

This study evaluates the operational status of twenty-six biofilter facilities across nine cities in Sweden, with respect to their functional design criteria, engineered design features (filter media composition, hydraulic conductivity, and drawdown time), and includes a visual inspection of the biofilter components (pre-treatment, in/outlet structures, filter media, and vegetation). These indicators were used to examine the performance level of each biofilter in achieving their design objectives set by the operators. Furthermore, it was investigated whether the biofilter facilities had been properly maintained to meet the objectives. Results indicate that the soil media used was consistent with respect to percentage sand, fines, and organic matter and comparable to design recommendations used by municipalities in other countries. The field-tested hydraulic conductivity for the biofilters ranged from 30 to 962 mm/h. This range of values, along with noticeable sediment accumulation within the biofilter indicate that not all the sites were operating optimally. Pre-treatment stages in poor condition with high volumes of sediment and litter accumulation were the primary causes for, and indicators of, low hydraulic conductivity rates. The ponding volume calculations revealed that at least 40 % of facilities did not have enough capacity to retain every-day and/or design rainfall due to design and/or construction flaws. These analyses raise concerns that, for a considerable number of the biofilters surveyed, water retention and flood protection identified by operators as prioritised objectives are not being met. This raises significant concerns about the functionality of biofilter in practice. Finally, some suggestions are given for tackling the design and maintenance problems discovered.