Sustaining Sherman Island: A Water Management and Agricultural Diversification System Richard Fisher1, Cory Miyamoto2, Kim Nguyen3, Ryan Whipple4 1Civil and Environmental Engineering, College of Engineering University of California, Berkeley 2Civil and Environmental Engineering, College of Engineering University of California, Berkeley 3Civil and Environmental Engineering, College of Engineering University of Calirfornia, Berkeley 4Biological Engineering, College of Engineering University of California, Berkeley Department of Civil & Environmental Engineering, University of California, Berkeley BSJ Keywords: Water management, flooding, aquaculture, agriculture, Sacramento-San Joaquin Delta, levees, wetlands, sustainability, global climate change, environmental impacts ABSTRACT The Sacramento-San Joaquin River Delta is that can actively protect against flooding disasters the main water resource for California’s urban by reversing subsidence and stabilizing levees, has and agricultural development. Sherman Island the ability to sequester carbon and restore habits, sits on the western edge of Delta system and is and the capacity to produce economic yields. The one of the key geographic features in balancing environmental, technical, and economic attributes the flux of saltwater into the Delta. Flooding, of the system are examined through failure saltwater intrusion, and ongoing subsidence are simulations, economic analysis, and environment current threats to Sherman Island. The integration discussion to determine if the proposed system is of components of aquaculture, hydroponics, and a feasible, sustainable and profitable solution for a levee enclosed flood storage area create a system Sherman Island and the Delta. INTRODUCTION Deltas are the pinnacles of life: they provide and towns, and 75,000 acres of undeveloped land from resources for a diverse array species and it is therefore flooding and saltwater intrusion the Delta is home to critical that we protect them. After describing the nearly 515,000 people living in seven counties, 500 current issues facing the Sacramento San Joaquin River different plant and animal species, including 20 that Delta, CA, US, this report will describe a case study of are endangered and major transportation and utility a water management and agricultural diversification infrastructure. (Department of Water Resources system at Sherman Island which can serve as a 2008) The Sacramento, San Joaquin, Mokelumne, demonstration project for future application to deltas Cosumnes, Calaveras Rivers and their tributaries flow around the globe. into the Delta and provide water to over 22 million The magnitude and diversity of California’s Californians – over two-thirds of the population. agricultural, environmental, industrial, recreational, Sherman Island sits on the western edge of the and urban interests in the Sacramento-San Joaquin Sacramento-San Joaquin River Delta and is one of the Delta emphasize the importance of protecting the Delta infrastructure. Protected by 1,100 miles of levees 1Corresponding author: for questions, contact Richard Fisher. are over 538,000 acres of farming, 64,000 acres of cities Phone number: (831) 246-4931 E-mail: [email protected] Berkeley Scientific Journal • Science fiction • Volume 15 • ISSUE 2 • 1 key geographic features protecting the Delta as a water combination of increased sea level and major storm in the hydroponics components. Each aquaponics resource. The island is located northeast of the city of events would pose an even greater risk to the system. system consists of fish rearing tanks, solids settling Antioch, California, and lies within the jurisdiction of While sea level rise has greater impact on long- and removal tanks, a bio-filter, the hydroponics rafts Sacramento County. The Sacramento and San Joaquin term water level variations, it is changes in river flow and a sump. The first step of the aquaponics cycle is rivers meet at its western boundary, which is bordered that have the biggest effect on a short-timescale for the fish eat food and excrete ammonia rich effluent. The to the northeast by Three-Mile Slough. Levee instability Delta (DRMS, 2008). Most predictions indicate that effluent is sent through the settling tanks to reduce caused by continued subsidence in the region is a there will be increased flows during the winter months the amount of suspended organic matter. Next the severe risk to cause catastrophic failure. and reduced flows in spring and summer. From a ammonia is removed and bacteria convert ammonia If Sherman Island’s levees were to fail water quality water resource perspective, this implies that less and nitrites to nitrates in the bio-filter. The nitrate rich for the entire Delta and most of California, would be water will be available as the state approaches times water is then pumped to the hydroponics component compromised, most likely on a timescale of years to of warmer temperature and increasing agricultural where plants’ roots hang into the pipes and absorb the Figure 1. Water circulation through Aquaponics System (Rakocy decades. Because residents rely on the Delta for their demand. Furthermore, reduced spring flows will nutrients from the water. Once water has reached the 2006). drinking water numerous health issues would result invite saltwater intrusion further inland into the Delta end of the hydroponics component, it is collected in from the Delta being compromised. In addition, the at a time when even less water will be available to a sump and then returned back to the rearing tanks. hydroponics rafts that can move up and down with livelihoods of those who utilize the freshwater, such as flush the system and maintain the integrity of water (Rakocy 2006) The water flow through the aquaculture the variations of the water levels but are anchored farmers and industry works, could deteriorate. Delta supplies. and hydroponics systems is shown in Figure 1. to prevent lateral movement. In addition, the flood Bearier Engineering estimates the cost to recover lost While it is difficult to apply global climate change The aquaculture components sit outside of the storage zone provides wetland acreage for wildlife water supply and to repair levees, infrastructure, and models to smaller scale regions such as the Delta, it flood management zone while the hydroponics and habitat restoration, recreation, carbon sequestration, damaged homes in the event of levee failures to be as can be inferred from the available studies that wind wetland systems dwell within. The flood storage zone and subsidence reversal. Levees and Siphons function high as $2.2 trillion (Delta Bearier Engineering 2009). velocity and intensity will increase in the area. The spans 800 acres and is able to store 12,000 to 16,000 to enclose the flood storage zone, transport and store BSJ The increased salinity due to saltwater intrusion will serious implications of this matter are that wind acre-feet of water. Figure 2 displays the approximate water during high river water levels as shown in also likely destroy populations of wildlife species. The velocities in the Delta region determine wind and layout of the system which consists of floating Figure 3. loss of species has the ladder effect on the diet and wave action, two factors which have a significant shelter of other species; thus, whole ecosystems are impact on levee erosion (DRMS, 2008). Consequently, BSJ susceptible to deterioration. levees weakened by wind and waves are subject to greater risk of failure in the event of high water or METHODS AND MATERIALS severe storm. Changes in average temperature and the amount CLIMATE CHANGE CONSIDERATIONS and type of precipitation are also expected as part Global climate change is a daunting but undeniable of global climate change. The amount and timing reality, the impacts of which must be considered. of annual runoff is one of the biggest impacts, as Engineered systems must be designed with these precipitation normally falling in the form of snow will effects in mind if they are to remain resilient over the turn to rain, reducing the amount of water available entire life span of the project. In considering just how for spring flows from snow melt (CA CCC, 2009). climate change will affect the Sacramento-San Joaquin Increased temperature will have significant effect on Delta, it is important to evaluate the following: the temperature gradient between the San Francisco Sea-Level Rise Bay Area and the Central Valley, further increasing Numerous scenarios and global climate models the intensity of wind velocities (DRMS, 2008). Warmer (GCMs) have been developed to predict the effect of temperatures will also lead to earlier melting of climate change on global mean sea level (GMSL). The snow, resulting in reduced water availability for Intergovernmental Panel on Climate Change (IPCC) an agriculture-dependent state already plagued by gives an estimated increase in GMSL of 0.1 m - 0.9 drought. Figure 2. Water management system layout. m between the year 1990 and 2100 (DRMS, 2008). Similarly, a more recent study suggests sea level will SYSTEM OVERVIEW rise by as much as 0.5 m to 1.4 m over the course of the Any proposed system for Sherman Island and next century (DBE, 2009). any Delta system must consider the needs of global There are several implications for Sherman Island climate change including: flood control, agricultural and the Delta given these predictions. Governed by development, water quality, and environmental significant tidal inflows, the Delta is very