Impact of Human Waste Disposal on Surface Water Runoff: The Muir Snowfield, Mount Rainier

Article excerpt

Introduction

As is typical of many of our national parks, Mount Rainier National Park has experienced a consistent increase in visitors since it was established in 1899 (1). Located in the Cascade Mountain Range in west-central Washington, the 14,411-foot (4,392.47- meter) peak shoulders 28 glaciers and unnamed snow patches containing a total of 156.2 billion [feet.sup.3] (1.1 [miles.sup.3]) of ice (2).

Of the over two million annual visitors, a growing number of climbers attempt to climb to the summit of the mountain. While less than 1,000 climbers attempted the summit in 1960, 9,220 registered to climb in 1994, with 4,411 (47.8 percent) succeeding (1). The majority of climbers use the Muir Corridor, climbing the Skyline Trail to Pebble Creek at 7,200 feet (2,194.6 meters) where the Muir Snowfield begins. The trail then leads over the snowfield to Camp Muir at 10,188 feet (3,105.3 meters) where the climbers spend the night. Climbers and day hikers eliminate urine and feces within rock fell fields and within the snowfield all along the route to Camp Muir. At the camp, a solar-assisted toilet is available for use. The liquid contents of the toilet are drained manually to unconsolidated soils beneath the permafrost while solids are flown out by helicopter (3).

The park has received an increasing number of complaints about foul odors from urine and feces along the route and at Camp Muir (4). The park has developed a growing concern regarding acceptable methods for feces disposal and the potential for subsequent surface water contamination (1). Since a typical climb lasts a minimum of two days, the need to travel light necessitates using either surface water sources or melting snow/ice to replace water consumed on the ascent. Park rangers recommend field water filter/pump units and/ or boiling melted snow/ice for drinking water.

Although many climbers are properly equipped to obtain safe drinking water, these units and practices are of course not universally available or applied. Also, many day hikers fail to take adequate quantities of water for the length of their hikes and commonly obtain free running surface water and drink it untreated. Although there appears to be a potential for disease transmission, the park is currently unaware of any reports of visitors/climbers contracting waterborne diseases during their visits (1). In 1983 the park began to prioritize the human waste management issue and, following several years of growing numbers of complaints, decided to assess runoff for the presence of fecal indicators (1). Since human waste disposal appears to be a problem in other climbing areas (both alpine and non-alpine), findings will have importance for human waste disposal in other areas as well.

In September 1994, following a warm summer and extensive melting of the snow field, the liquid contents of the solar-assisted toilet at Camp Muir were drained. Some of this water apparently surfaced and created odors leading to complaints from climbers (1). Samples taken of runoff suspected of being contaminated by these toilet wastes revealed the presence of ammonia and elevated levels of TDS and conductivity (1). This is what precipitated this study.

Purpose and Scope

The purpose of this study was to attempt to determine if surface water runoff from the Muir Snowfield was contaminated with human wastes, and, if so, attempt to determine the flow path(s) of these runoff materials. Computer models indicate that runoff flows through the Muir Snowfield in an underdrain system beneath the snow and underlying permafrost, and cascades over cataracts into the valley of the Nisqually Glacier one-half mile from Camp Muir. The study focused solely on the Muir Snowfield. The upper boundary of the study area was Camp Muir; the lower boundary was Pebble Creek at the Skyline Trail crossing. Anvil Rock, Moon Rocks and the fell fields to the east of the snowfield formed the eastern boundary, and the fell fields and margin of the Nisqually Glacier valley to the west formed the western boundary. …