Secondary Economic Impacts of a Reduced Bay Area Water Supply

Key Findings

  • Large water supply shortfalls during dry years
  • Severe dry-year water rationing in the RWS service area
  • Building moratoria in affected cities
  • Higher Bay Area housing costs
  • Increased price of water within the RWS
30% Unimpaired Flow Requirement on the Tuolumne River
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40% Unimpaired Flow Requirement on the Tuolumne River
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50% Unimpaired Flow Requirement on the Tuolumne River
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Unimpaired Flow Impacts
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州水资源控制委员会负责为流入萨克拉门托-圣华金三角洲的河流设定流量目标,以保护水资源的有益利用. 委员会正在考虑旨在改善圣华金河渔业的新法规. The regulations, 正如海湾三角洲水质控制计划的替代环境文件草案(SED)所详细说明的那样,在2月至6月期间,允许平均40%的河流的自然流量从La Grange流入萨克拉门托-圣华金三角洲, 根据条件的不同,自适应实现范围在30%到50%之间. 通过减少圣华金河三条主要支流(默塞德河)的引水,就可以实现流量目标, Stanislaus, and Tuolumne Rivers. 图奥勒姆河是赫奇赫奇地区水系(RWS)的主要水源。, 由旧金山公用事业委员会(SFPUC)拥有和管理.

In an average year, 图奥勒姆河大约48%的水被用于中央山谷的农业, 38 percent remains in the river, and 14 percent is diverted by the SFPUC. 来自Tuolumne河的水是SFPUC的RWS的主要(85%)供应.6 million people in San Francisco, Silicon Valley, and the East Bay. 在干旱年份,图奥勒姆河只有10%的水残留在河里. According to this analysis, 要满足战略经济对话在干旱年份增加的流量要求,就需要大幅削减旧金山湾区的供水, the Central Valley, or some combination of both.

The draft SED does not explain how the cuts would be allocated across users; SFPUC estimates it could be responsible for providing as much as 51 percent of any new flows required. Under that scenario, SFPUC analyzed flow data on the Tuolumne River going back to 1920, 并根据5个不同的变量估算了到2010年,湾区零售和批发客户每年可获得的水量:20, 30, 40, and 50 percent unimpaired flow, as well as a “base case” without an unimpaired flow standard. SFPUC repeated the analyses under three different demand scenarios: A system-wide demand of 265 million gallons per day (MGD) to represent future conditions; demand of 223 MGD to represent current system demand without rationing and equivalent to deliveries made in FY 2012-2013; and lastly, 175 MGD的需求代表当前的系统需求,包括相当于2015-2016财年交货量的干旱配给.

The Bay Area Council Economic Institute looked at the impacts a 30, 40, 在175毫克毫克的情况下,图奥勒姆河50%的未受损流量需求将对湾区用水用户产生影响. 之所以选择175 MGD情景,是因为它准确反映了最近(2015-2016年)的干旱年需求, 因此,这代表了当前居民可能面临的最坏情况, 城市规划者在评估新开发项目可用的供水时将被迫考虑.

The key takeaways from this analysis are as follows:

The draft SED could lead to large water supply shortfalls during dry years
According to the SFPUC, 在诸如1990年等干旱年份,RWS供应将从175毫克毫克d减少到67毫克毫克d, 1991, 1992, resulting in a maximum annual shortfall of 120,976 acre-feet. The shortfall would have to be addressed either through conservation, the creation of new water supplies, or a combination of both.

Using conservation only, 在干旱年份,RWS用户可能被迫减少55%的用水量到每位居民用户每天30加仑(R-GPCD). 许多城市面临的R-GPCD要求要低得多,比如门洛帕克只有8.57 gallons. RWS customers currently use 54 R-GPCD, the lowest in California. The California statewide average is 82 R-GPCD.

The draft SED could result in building moratoria in affected cities
Residents in Melbourne Australia, widely regarded as one of, if not the, most water efficient cities in the developed world have achieved 40 R-GPCD. 我们假设,任何一个湾区城市,如果被迫规划干旱年的R-GPCD水平低于35加仑,将被迫对新许可采取临时控制措施,并暂停新建设.

The draft SED could result in higher housing costs in the Bay Area
加州立法分析师办公室发现,建造的房屋少于人们的需求会推高房价. Had the draft SED been put in place in 1990, 加州财政部提供的最早的住房数据, we estimate the multiple building moratoria could have resulted in 91,098 fewer housing units over the period ending 2015. Over the same time period, the RWS service area attracted 302,435 new residents. Additionally, SFPUC estimates RWS demand will increase to 265 MGD in the future, meaning the gulf between the Bay Area’s supply and demand will grow over time, further negatively impacting affordability.

The draft SED could undermine Bay Area economic growth
The region served by the RWS supports 3.3 million jobs and generated $667 billion in GDP in 2015. 暂停新开发将直接削弱旧金山湾区雇主在该地区增长和创造就业的能力. Indirectly, 旧金山湾区的雇主越来越多地指出,住房短缺是阻碍他们在旧金山湾区发展的一个重要因素, 并报告将新的工作外包给住房供应更实惠的地区. 通过加大建设难度和成本,SED将加强这一趋势.

The draft SED could increase the price of water within the RWS
通过确保新的供水,可以避免或部分减少上述影响. Due to chronic water supply deficits throughout California, we assume SFPUC will be unable to secure long-term contracts for imported water, 取而代之的是必须通过海水淡化或水循环利用来创造新的水源. During dry years at 175 MGD demand, SFPUC estimates the RWS supply will be reduced to 67 MGD, a supply gap of approximately 121,000 acre-feet per year. 通过脱盐生产如此数量的水每年估计需要$ 2.58亿至$ 2.86亿, 对纳税人而言,净成本增加约3,800万至6,600万美元. 由于缺乏类似规模的项目,水循环利用没有被考虑.