Hooffs Run (Alexandria, VA) Watershed

  Hooffs Run Bridge (Jamison Ave) in Old Town Alexandria, looking north.  Source: Bridgehunter.com I decided to research watershed monitoring equipment that could be used by ‘citizen scientists’ within the Hooffs Run watershed. This could be done for personal interest, or more ideally, as part of a watershed wide effort by residents to collect and analyze information relating to water quality. Data collected by individuals could be aggregated to form a better picture of overall water quality with the watershed. Perhaps it could also be compared against results in the other watersheds within the City of Alexandria.  A good monitoring kit for citizen science efforts is the LaMotte Low Cost Water Monitoring Kit . The kit is compact and is relatively cheap at US$43.75 on the LaMotte website. This kit seems to be a market leader in the low cost segment, and allows for the testing of eight different factors:   Ph Dissolved Oxygen BOD Nitrate Phosphate Temperature Turbidity Coliform Screeni

Photo Source: Discover Magazine The environmental impact of free ranging domestic cats within the Hooffs Run watershed will be addressed in the post. According to the Audubon Society of Northern Virginia (ASNV), free roaming domestic and feral cats are the second biggest driver of the decline in birds in the US and Canada. Furthermore, “free roaming cats threaten birds and other wildlife, disrupt ecosystems, and spread diseases.” The Wildlife Society notes that free roaming cats “decrease native wildlife abundance and diversity, especially of species that nest on or near the ground”, and are responsible for “at least 33 bird species globally”. Within the Hooffs Run watershed it is difficult to determine exactly which birds are at most risk from free roaming cats, but Mourning Doves, Sparrows, Northern Cardinals, Starlings and Blue Jays are likely to be at high risk given their prevalence. In 2016 the Smithsonian Magazine reported that "Americans own about 86 million cats, o

A future project is to convince the City of Alexandria to procure a mobile app that can be used to conduct a 'Frog Census' within the Hooffs Run watershed. Melbourne Water in Victoria, Australia, offers an excellent app that can be used by citizen scientist to record the location of frogs within the City of Melbourne.  A short instructional video on YouTube can be found through this link , and an article highlighting how successful the citizen scientists effort has been can be found through this link.   In short, members of the public download the app, then use it to document the locations of frogs. The type of frog is detected through the app based on the sounds the frog makes. Melbourne Water then monitors the program and can then manage the urban habitat accordingly. Here are a couple of screen shots from the instructional video. Undertaking a similar effort within Hooffs Run would be an interesting way to learn more about the local frog population. By some estimates , there

The main threat to the Hooffs Run watershed is runoff extremes due to the highly urbanized nature of the City of Alexandria. The prevalence of impervious surfaces, and absence of a residential storm water  management strategy implemented by private home owners to complement the city’s storm water  management system, results in localized flooding and possibly the flow of toxins in to the Potomac River. Urbanization and the road network may also be leading to non-native plant invasion within the Hooffs Run Watershed based on a 2017 study. According to an article in the ‘Biological Invasions journal’ authored by Dennis Skultety and Jeffrey Matthews, “Human modification of the landscape, including urbanization and road construction, has facilitated the spread and establishment of non-native plant species” (Skultety & Matthews, 2017) . The authors further conclude that heavily urbanized areas have a “combination of factors making them susceptible to invasion” and the “impacts of urb

Hooffs Run Watershed - Flooding Flooding is a topical issue for many residents living in the Hooffs Run watershed, particularly those in Del Ray neighborhood. The most recent Rain Event on September 10, 2020, resulted in 315 requests for service from local residents. While a USGS monitoring station within the Hooffs Run watershed could not be located, USGS 01653000 monitors the nearby Cameron Run, which displays a significant increase (discharge, cubic feet per second) on September 10, 2020. The map below highlights a residential area that is reportedly subject to frequent flooding, which is also highlighted in the City of Alexandria ‘heat map’ of service calls from September 10, 2020. Source: City of Alexandria Presumably the highlighted area is at, or near, sea level, and during rain events a significant amount of water flows down from the hilly area west of Russell Road overwhelming the storm water system. The flow of surface, and subsurface water, may follow the direction of th

    Hooffs Run Watershed - Characteristics and Features. Storm water and Sewers:   As outlined on the  City of Alexandria website , the city operates two types of storm sewer systems: A separate sewer system and a combined sewer system (CSS). The separate system consists of two pipes (one each for sewer and storm water), where as the CSS combines sewer and storm water in a single pipe. During moderate to heavy rain, the pipe can become overloaded with storm water and raw sewage may overflow in to local streams (including the Hooffs Run Stream/Tributary).  The Hooffs Run watershed encompasses both systems, although the majority of the watershed surface area is serviced by the separate system. The Hooffs Run stream, seen in the map below, holds significance as it is the site of two CSS Combined Sewer Overflow (CSO) Stations (red dots 003 and 004). A detailed GIS Sewer Viewer maintained by the City of Alexandria displays how storm water and sewage are collected in old town, then