The population surround the sound also includes many that rely upon its waters. These include 4.4 million people; about 67% of Washington State’s entire population. There are also 118 incorporated cities and towns, 15 American Indian tribes, and 12 bordering counties — Clallam, Island, Jefferson, King, Kitsap, Mason, Pierce, San Juan, Skagit, Snohomish, Thurston & Whatcom. More than 3.6 million (about 80% of Puget Sound residents) live in King, Kitsap, Pierce, and Snohomish counties alone (WSDOE, 2011).

The sound has geographic features that include 2,800 miles of inland marine waters, 2,500 miles of shoreline, 19 river drainage basins and 2 mountain ranges (the Olympics and the Cascades). The average depth of the Puget Sound is 140 meters and the deepest point reaches a great 280 meters, which is located just north of Seatlle (WSDOE, 2011).

 The Puget Sound surrounds much public land that is utilized as well. Sixty eight state parks, 16 regional parks, 8 national parks and forests, wildlife refuges, and other federal lands, and 21 million acres of state-owned submerged saltwater lands are all included (WSDOE, 2011).

Within Puget Sound, tides are of the mixed type in which two highs and two lows occur each tidal day. Heights of low waters generally have the greater variability. “Thus each tidal day there occurs a Higher High Water (HHW), a Lower Low Water (LLW), a Lower High Water (LHW), and a High Low Water (HLW). Heights and ranges of the tides vary between Spring Tides (larger tides) and Neap Tides (smaller tides) over a period of 14.3 days. the tides never exactly repeat, but the closest repetitive cycle is approximately 18.5 years, the period of the rotation of the Moon's node” (Lincoln, 2000).

The Puget Sound has several different inputs of water that end up contributing to the total amount that resides in the sound. The inflow/outflow from the ocean through the Strait of Juan de Fuca has an average mean tidal exchange of 5.25 cubic km (Lincoln, 2014).

The total flow from wastewater treatment plants and industrial facilities to Puget Sound is 390 million gallons per day, which converts to 0.539 cubic km per year. This is about 1.3% of the all the freshwater inflows from the rivers and streams to Puget Sound, by volume (WSDOE, 2011).

Storm water runoff is rain that falls on the street, sports fields, gravel lots, rooftops, parking areas, and other developed land and flows directly into nearby lakes, rivers, and Puget Sound. The rain picks up and mixes with what is on the ground, and in most of the area’s storm water runoff enters these waters without being cleaned of pollutants. Several varieties of products can get mixed with the water. Different categories include oil, grease, metals and coolants from vehicles; fertilizers, pesticides and other chemicals from gardens and homes; bacteria from pet wastes and failing septic systems; soil from construction sites and other bare ground; soaps from car or equipment washing; and accidental spills, leaky storage containers, tobacco spit and whatever else ends up on the ground. The average storm water discharged in the Puget Sound region each day is about 675,000,000 gallons (0.002555153 cubic kilometers). On an average day, an estimated 140,000 lbs or 6.4x10^-7 cubic kilometers of toxic chemicals ranging from petroleum to polychlorinated biphenyls (PCBs) enter Puget Sound (King County, 2013).

Average annual precipitation in just the Puget Sound is 11.57 km³ (Climate Data Online Annual Summaries, 2013). The Puget Sound basin receives most of its precipitation in the winter, whereas municipal water use is greatest in the summer. Most of this increase in demand is for residential and commercial landscape irrigation. In the Pacific Northwest, heavy winter precipitation poses challenges in managing floods while extended periods of low precipitation in summer and early fall prove difficult in meeting public water demands and in maintaining environmental purpose demands as well. In the summer and fall, reservoirs and storage of winter precipitation in mountain snowpack to provide inflows into reservoirs are replied upon (Vano).

Sampling different areas of Puget Sound requires different techniques. For example, a deep station in the San Juan Islands may have a zooplankton tow, but a shallow station in Quartermaster Harbor may only need a surface phytoplankton sample. For the most part, similar data was collected in all stations and on average each station would involve most of the following processes. A CTD was lowered to electronically collect data from the entire water column. After returning to the surface, the instrument was connected to a computer and the data was downloaded. Niskin bottles were also closed at depth and surface to collect water samples. From the bottles, dissolved oxygen, chlorophyll, and nutrients samples were fixed and stored for later lab processing. Secchi disks were used to estimate the penetration of light into the water. Selected sites had sediment graphs, deep plankton tows and surface plankton tows. For a detailed explanation of individual processes, please visit the equipment and methods age.

Estuaries Field Studies (TESC 445) is a field course focusing on the physical, chemical and biological properties of various bodies of water in the Puget Sound. The class sampled four distinct areas of the Puget Sound; Commencement Bay, Quartermaster Harbor,San Juans, and Hood Canal. This website contains all the information for each area of which samples were collected and analyzed, and all the sites are linked from this homepage.

All the data was collected at each area of the Puget Sound. Each area had multiple locations referred to as ‘stations’. The study focused mainly on chemical analysis, physical conditions, and biological and geological measurements. All samples were taken back to the laboratory for analysis. Certain collected samples were sent to  the Center for Urban Waters and University of Washington Seattle for analysis. The sample data that was collected at each station included: temperature, salinity, density, oxygen, fluorescence/chlorophyll, transmissivity, nutrients, phytoplankton, zooplankton, sediments, and microplastics. The description of the methods used at each sampling station can be found on the methods page.