What Water Quality Parameters Does EarthViews Measure?

Water Quality Data Collection

Often when we are setting up to go map an area people will pass buy and ask about the different sensors being used. When we bring up the fact that we are collecting water quality measurements in concert with each geolocated 360-degree panoramic image the next question is always, what are you measuring in the water? So here is an answer as it relates to the nearshore mapping we are doing in Puget Sound. 

Puget Sound Water Quality

Puget Sound is a fjord with a diverse bottom bathymetry. It also has a diverse nearshore, encompassing urbanized, sub-urban and more natural shorelines. This diversity is the result of the size of the waterway, making up nearly 1300 miles of shoreline. Because of its shape and size many areas create bottlenecks to seawater exchange from tidal influences. This can result in long long times for seawater to remain in certain areas exacerbating any negative impacts to water quality by people. Marne life in the Sound has evolved to be very specific with regards to habitat and water conditions. Degradation of these water quality parameters therefore can have lasting impacts.

  • One of the major concerns right now is acidification. pH of the water can decrease as a result of large amounts of carbon dioxide in the water. These levels have been decreasing because of climate change, destroying the calcium shells of baby oysters, clams and other shellfish, making it hard for them to reproduce. 
  • An equally problematic human induced water quality problem in Puget Sound is wastewater contamination from sewer overflows and leaky septic systems. The extra nutrient inputs from this contamination can cause harmful algal blooms which make shellfish poisonous. These blooms can also create eutrophication depleting certain areas of oxygenated water, creating “dead zones” where nothing can live. These zones have been seen at certain times of year in Hood Canal where tidal seawater exchange is slow. 
  • Toxic heavy metals are another source of severe impacts to water quality. These metals were, and still are introduced in urban industrial settings. Some of these areas have become SuperFund sites where hundreds of millions of dollars are spent to eliminate legacy pollution impacts.

Water Quality Fundamentals 

When measuring water quality scientists test three major categories: physical parameters like temperature, pH, and dissolved oxygen, biological parameters like bacteria levels and chemical levels like PCB’s. We focus on the following physical parameters: Temperature, pH, Dissolved Oxygen, and Salinity. Below is a table describing the specifications of the measurements collected by the instrument we use.  

Hana Water Quality Measurement Specifications

pH range0.00 to 14.00 pH
pH accuracy+ or – 0.02 pH
pH/mV input range+ or – 600.00mV
pH/mV input accuracy+ or – 0.5mV
ORP range+ or – 2,000.0mV
ORP accuracy+ or – 1.0mV
Dissolved oxygen range0.0 to 500.0% / 0.00 to 50.00mg/L
Dissolved oxygen accuracy0.0 to 300.0%, + or – 1.5% of reading or + or – 1.0% (whichever is greater)300.0 to 500.0%, + or – 3% of reading0.00 to 30.00mg/L, + or – 1.5% of reading or 0.10mg/L (whichever is greater)30.00mg/L to 50.00mg/L, + or – 3% of reading
Conductivity range0 to 200.0mS/cm (absolute EC up to 400mS/cm)
Conductivity accuracy+ or – 1% of reading or + or – μ/cm, whichever is greater
Resistivity range0 to 999,999Ωcm; 0 to 1,000.0kΩcm; 0 to 1.0000MΩcm
Resistivity resolutionDependent on resistivity reading
TDS range0 to 40,000mg/L or ppm (maximum value depends on TDS factor)
TDS accuracy+ or – 1% or + or – mg/L (ppm), whichever is greater
Salinity range0.00 to 70.00 PSU (Extended Practical Salinity Scale)
Salinity accuracy+ or – 2% of reading or 0.01 PSU, whichever is greater
Temperature range-5.00 to 55 degrees C/23 to 131 degrees F/268.15 to 328.15 degrees K
Battery type(4) 1.5V alkaline C cells, or (4) 1.2V rechargeable C cells
WeightMeter 750g/26.5oz.; Probe 750g/26.5oz.
Dimensions221 x 115 x 55mm/8.7 x 4.5 x 2.2 inches (H x W x D)

EarthViews Methods

We take surface level measurements which means they are taken at a meter or less depth. Most of the time surveying the nearshore we are in water that is shallow. Before each survey we calibrate the instrument to make sure the measurements are accurate. These measurements provide a good baseline of conditions and provide information that can be used to find areas that one would want to explore in more detail and with greater scientific rigor. 

Understanding Nearshore Matters

Water quality is directly related to the land water interface and improving Puget Sound water quality will require having the best possible understanding of what those nearshore conditions are like. This understanding is at the heart of our mission. 

Kayaker crowdsourcing imagery for mapping project with EarthViews.

Mapping with Crowdsourcing at EarthViews

We are fortunate at Esri to have a wide array of business partners that are helping us achieve a more sustainable and resilient planet.  One of these business partners is EarthViews.  EarthViews vision is to connect people to critically important aquatic and terrestrial ecosystems. EarthViews works with land, water managers and others to help achieve this mission.  To accomplish EarthViews’ vision, they have developed technology to bring waterways to the desktop, mobile or VR device via easy-to-use, publicly available, 360 interactive virtual tours. These reality based maps have many uses for waterway safety, recreation, science, and conservation. Mapping with crowdsourcing at EarthViews helps with the mission.

One of my favorite teaching tools is their EarthViews Atlas.  I use these immersive videos and stills to help students understand how waterways in urban and rural areas are so critical to water quality and quantity, to ecosystem health, to human health and wellness, and to recreation.  They are somewhat like “Google Street View” for waterways!  Some are taken on the water, and some are even taken underwater!  One of my favorites is the fascinating 360 degree views of the Okavango Basin in Angola, Namibia, and Botswana.  My central message to students is that rivers, ponds, and lakes are not just expanses of blue depicted on maps!  They have width, depth, chemistry, and many other characteristics that EarthViews helps us to understand.

I also frequently refer to EarthViews in my career presentations for students:  (1)  Be innovative!  EarthViews found a need and created a company and a set of tools to meet that need.  Consider doing the same for an area you see a need in!  (2) Consider working for one of our business partners when you see openings.  The Esri partner network includes people in just about every possible field, including natural resources, public safety, mapping, planning, health, business, city planning, transportation, and many more. 

One of the educational and societal forces I and others frequently teach about is crowdsourcing.  Crowdsourcing is possible via field apps such as Survey123, iNaturalist, and many others.  Instructors have been using crowdsourcing with their students to generate data on invasive species, weather, soil chemistry, litter, graffiti, vegetation, vehicle and pedestrian counts, walkability (as I describe here), and many other phenomena.  However, it is still sometimes challenging to find meaningful crowdsourcing activities for students and others that will actually be used over the long term by those outside one’s classroom.  Once again, I turn to EarthViews for a wonderful opportunity.  EarthViews has a crowdsourcing opportunity that you and your students could participate in.  Yes, you and your students can help EarthViews create the immersive imagery that I described above in their atlas!

Join the EarthViews crowdmapping team and get the areas you care about published on EarthViews Atlas!  Mapping by crowdsourcing is easy at EarthViews. They even have cameras and mapping gear to loan out to volunteers! 

This blog post was written by Joseph Kerski GISP at esri and originally appeared here.