John Nguyen Lake Merritt Nitrogen Project May 9, 2005p. 1Lake Merritt Nitrogen ProjectPinpointing Nitrate Contributions to Lake MerrittJohn NguyenAbstract High-quality golf courses and cemetery landscapes require substantial pesticide andfertilizer applications, leading to concerns about their environmental impacts. Anthropogenicsources of nitrogen coming from highly fertilized lawns of the Claremont Country Club (golfcourse) and the Mountain View Cemetery, both located in the upper urban watersheds ofOakland, California, were hypothesized to be the major contributors of the nitrogen loading. Astudy was conducted to locate the origin of nitrogen loading into Lake Merritt from itscontributing waterways. Runoff from the Claremont Country Club and the Mountain ViewCemetery flows into Glen Echo Creek, the adjacent waterway that drains into Lake Merritt. Thisstudy includes monitoring nitrate levels above and below these sites in order to evaluate andlocate the source of the nutrient load further downstream and in Lake Merritt. The golf courseand cemetery management practices did not appear to be the main contributors of nutrientloading into Lake Merritt. High upstream concentrations of nitrate in Glen Echo Creek indicatedcontamination above these locations. However, monthly sampling also revealed increases indownstream nutrient concentration below these sites. Therefore, fertilizer applications andmanagement practices at the Claremont Country Club and the Meadow Wood Cemetery appearto contribute some N loading, but much of the N loading above these two sites appear tocontribute more to long-term stream and lake nutrient enrichment. Further research above thelocations is needed to conclusively identify the major nutrient contributor to Lake Merritt.John Nguyen Lake Merritt Nitrogen Project May 9, 2005p. 2IntroductionFor as long as humans have lived near waterways, they have used them to wash away theirwastes and pollutants. With the growing population and increased production and consumption,this tradition of flushing wastes downstream has overwhelmed the cleansing capacities of theEarth’s water (Carpenter et al. 1998). As a result, water quality in rivers, lakes and coastaloceans has degraded over recent decades. This degradation is demonstrated by the disruption ofaquatic ecosystems and the decimation of the various inhabiting species as well as the amenitiesthat those ecosystems once provided to society (Carpenter et. al 1998).The most common impairment of surface waters in the United States is eutrophication causedby excessive inputs of phosphorous and nitrogen (Caraco and Cole 1998). There are three formsof nitrogen: dissolved organic nitrogen, dissolved inorganic nitrogen, and particulate organicnitrogen. Dissolved inorganic nitrogen consists of ammonium (NH4+), nitrate (NO3-), or nitrite(NO2-), which fosters the growth of bacteria, algae and higher plants (Seitzinger and Kroeze,1998).Lake Merritt, known as the “Jewel of Oakland,” suffers from excessive nutrient loading fromurban runoff. Low oxygen levels within the lake have classified the lake as an impaired body ofwater by the Environmental Protection Agency. The amount of nutrients drained into lakes ingeneral is significant when the rainfall flows over the creeks and into drainage lines that aredischarged directly into the lake (Klessig et. al 2004). It is speculated that increased urbandevelopment and recreational usages in the upper regions of Lake Merritt’s watersheds hasincreased the nitrogen and phosphorus load into the lake. The increased production andaccumulation of these nutrients stimulates eutrophication of the lake and its waterways.Unfortunately, water quality and general upkeep of the Lake has suffered in recent years dueto Oakland’s declining budget, and from the increasing pressures of an urban environment. As aresult, the City of Oakland’s Public Works Agency created a non-profit organization that nowoversees upkeep of the lake; the Lake Merritt Institute (Plearn 2000). Since its inception in1992, the Lake Merritt Institute has supported research funded by grants and public donations toimprove the environment of the lake, and as a result aeration fountains, tidal gates, flood dams,and weekly clean-ups have contributed to a healthier lake and preserved the habitat for manymigratory birds and aquatic species. The Lake Merritt Institute has continued to support severalJohn Nguyen Lake Merritt Nitrogen Project May 9, 2005p. 3water quality studies to pinpoint sources of additional pollution. This particular study is focusedon point sourcing nitrogen contributors to the lake.Second only to phosphorous, nitrogen is a limiting nutrient for plant and algae growth andmay enter the lake through an array of sources. Studies have shown that precipitation may be themain N source for seepage and some drainage lakes (Klessig et. al 2004). As excessive plant-algal growth dies, aerobic bacterial decomposers proliferate and break down the dead anddecaying plant matter. In this decomposition process, the aerobic bacteria consume dissolvedoxygen from the water, leaving oxygen shortages that causes fish kills (Carpenter and Ludwig1999). Alterations to the natural environment may decrease species population size, growthrates, reproductive success and survival rates, while others sky-rocket, disturbing the fragilebalance of ecosystem processes. Thus, overabundance of N loading plays a tremendous role incausing potential ecological destruction, and the subsequent loss of biodiversity (Vitousek et. al1997).The contribution of N from these watersheds into Lake Merritt has not been identified in thepast. This study was designed to obtain this data. NO3- levels and turbidity levels weremonitored for a full seasonal year, beginning in February 2004 through February 2005 from theGlen Echo and Trestle Glen Watersheds.The main creek in focus for this project is Glen Echo Creek found in the Glen EchoWatershed, whose banks are parallel to both the golf course and cemetery. These tworecreational areas are hypothesized to be the major nitrogen contributors to Lake Merritt becauseof the potential for fertilizers containing N compounds spilling over into the creek. Bycomparing the NO3- levels from the cemetery and golf course, both upstream and downstream,the primary focus of this study will identify the amount of N loading from these two locations totest our hypothesis that there is more N loading
View Full Document
Unlocking...