No abstract

Groundwater elevations in coastal cities will be affected by climate-change-induced sea level rise (SLR) and wastewater collection systems will experience increased groundwater infiltration (GWI) due to greater submergence of sewer pipes. Commercial sewer hydraulics models consider GWI to be a constant quantity estimated via a low-flow monitoring campaign and are incapable of predicting future flows due to changes in GW elevations. A global sensitivity analyses conducted for a two-dimensional GWI pipe flow model found the most important input parameters are groundwater head and surrounding soil hydraulic conductivity. Two case studies were conducted considering a range of pipe defect severity to estimate increases in GWI associated with predictions of future SLR. The findings are that SLR will begin to have noticeable impacts in terms of increased average dry weather flow (ADWF) as soon as 2030 (3–10%) and will increase dramatically in the future (10–29% by 2050, and 50% or more by 2100). Daily and seasonal tide ranges affect the normal diurnal flow variations by between 3% and 10%. The estimation methodology and case studies described here illustrate the coming future importance of SLR effects on GWI in coastal collection systems that should be included in facilities planning and design.

Collection systems in coastal cities are often below the groundwater table, leading to groundwater infiltration (GWI) through defects such as cracks and poor lateral connections. Climate-change-induced sea level rise (SLR) will raise groundwater levels, increasing the head and thus the inflow. A method has been developed to predict GWI when groundwater levels change using calibration with sewershed flow monitoring data. The calibration results in a parameter that characterizes the porosity of the collection system. A case study is presented for a coastal city with reliable flow monitoring data for eight days that resulted in a large range of effective defect sizes (minimum 0.0044 to maximum 0.338 radians), however, the range of predicted future GWI in currently submerged pipes varied by only 12% from the mean. The mean effective defect predicts 70 to 200% increases in GWI due to SLR of 0.3 to 0.9 m (1 to 3 ft), respectively, for currently submerged pipes. Predicted additional GWI for pipes that will become submerged due to SLR will increase GWI to values that approach or exceed the current average dry weather flow. This methodology can be used for planning of infrastructure improvements to enhance resiliency in coastal communities.

Accidental suffocation and strangulation in bed is a leading cause of preventable infant death. Bed sharing, teen motherhood, and Hispanic ethnicity have been associated with infant sleep suffocation death. Fifty-five Hispanic teen mothers were surveyed regarding acculturation/demographic characteristics and their infants' sleep behaviors. Most participants had 2 foreign-born parents from Latin America. Participants with 2 US-born parents were less likely to bed share than their less-acculturated peers. Many participants reported not always placing their infant in a supine sleep position. There is a significant need to reach out to Hispanic teen mothers, particularly from newer immigrant families, with culturally and linguistically appropriate multigenerational clinical messaging on the risks of infant bed sharing and nonsupine sleep positioning.