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美国专家H.Frederiksen专题演讲 -- 加州水资源开发利用
  2015-03-13 15:10  

Water Development and Management--Key to Californias
Social, Economic and Environmental Goals
Harald D. Frederiksen

 

Introduction

The depth of the Ministry / Bank / AusAID Strategy report and the findings of the analysis provide solid information for PRC and international entities to consider in formulating a comprehensive attack on the water problems facing China. The report sets forth a detailed assessment of the situation, consideration of various measures to address basic water quality and quantity problems and offers specific actions.

However, as the report infers, decisions must be taken now. The ten to fifteen years remaining until substantial results must be seen in the field, the very limited sources of financing for the huge capital and operating expenditures and the unpopular but essential modifications of present institutional arrangements, severely constrain choices. These three factors: time, financing and institutional change -- must be kept in the forefront during the deliberations and when selecting actions. And hovering over the debates is the potential for a devastating multi-year drought without having any significant reserves or means to augment supplies from other sources.

I have been asked to discuss water resources development and management in California, as it may provide some useful experience. Though on a much smaller scale, California has to deal with extremes in the quantity of water runoff. Only thirty-five percent of California's average annual 245 BCM of precipitation results in runoff. Of this 85 BCM runoff, 70% is available as renewable supply with 30% as flood flows in excess of in-stream needs, discharging to the ocean or saline sinks.

The State's total annual runoff, however, is highly variable. It has ranged from 18 BCM to 165 BCM within the last two decades. (And tree ring analysis shows that California suffered two epic droughts; one lasting two hundred years ending in 1112 and another lasting 140 years ending in 1350. During these periods there was no outflow from mountain lakes as confirmed by carbon-dating stumps of trees found ten to fifteen meters below the elevation of the bottom of the lakes' outlet.)

Except for the northwestern region, almost all of the state suffers from seasonally inadequate water supply. In several regions, particularly in the south and in its primary metropolitan areas, total annual runoff proved inadequate by the early 1900s. By 1998, the State's utilizable surface water was allocated 46% environmental, 43% agricultural and 11% urban with limited overdraft of groundwater in most regions.

As background, I would like to summarize the evolution of water management principles and policies adopted by the state. This will include discussion of the parallels with and differences from China's situation.

In a subsequent presentation, I will present information on the period from the 1950s until today, during which California's most massive water development, the California Water Project to convey water from the Northern California to Southern California  was executed with the parallel increased attention given to environmental issues.

Background

Over the past 150 years, California has developed one of the world's largest economies. It's current population of 35 million. The economy evolved in phases from mostly rainfed agriculture and mining; to expanded irrigated agriculture, fishing and light manufacturing; onto high technology, intensive irrigated agriculture and services. The climate of California has forced it to adopt increasingly more comprehensive resources management and development in advance of need to support this anticipated, but largely unquantified, growth.

The southern onethird of the state receives from essentially zero to 50 cm of precipitation. The northern regions average substantially larger amounts, particularly in the mountains where precipitation may exceed 225 cm. The snowmelt in the high mountains, a major water storage for the state, is released over a period extending into mid-summer. The normal flood runoff produces the primary supply for the reservoirs.

The water reservoirs and canals systems that serve over 80% of the land irrigated today was developed and self-financed by farmer-organized irrigation districts during the last thirty years of the 1800s and early 1900s. Private investors developed limited lands, however, all such irrigation schemes failed during economic recessions or droughts. By the early 1900s, every major city was importing water from outside their respective watersheds. San Francisco and the East Bay cities developed reservoirs in the Sierra Mountains and pipelines to bring water to their coastal regions. Los Angeles secured additional supply from the eastern slopes of the southern end of the Sierras.

In the early 1920s, the state formulated a loose framework plan for the ultimate development of the state's surface waters to serve the remaining lands suitable for irrigation and the expanding metropolitan areas. The plan was in response to local requests for a strategy to resolve the ever more difficult water situation facing farm and city areas alike as the population grew. The component of the plan was to build either by a state entity or local umbrella organizations -- large bulk water supply' schemes to serve the water districts and municipalities within the various regions.

The economic depression of the early 1930s left the state without a market for its contemplated financing bonds. It had to ask the Central government's US Bureau of Reclamation (USBR) to develop portions of the Central Valley's waters to augment the existing farmer-owned systems and expand irrigation on new lands. As a result, the USBR constructed the Central Valley Project from the late 1930s through the 1970s.

At the same time, The Metropolitan Water District of Southern California was created as an umbrella organization to contract directly with the US Bureau of Reclamation for water from Hoover Dam on the Colorado River. This water was to serve over forty irrigation districts and municipalities in Coastal Plain of Southern California. The initial USBR/MWD contract was for 40 years. Simultaneously MWD secured local financing to construct its Colorado aqueduct to bring water from the Colorado River to its member owners. The 140,000 hectare Imperial district, formed in the late 1800s, contracted with USBR for water from the same structure to firm up their variable supply.

The last major infrastructure undertaking outlined in the 1920's Plan was what evolved as the California State Water Project. This provides the major transfer of bulk water from Northern California to the western and southern Central Valley and on to the Metropolitan areas of Southern California, the San Francisco Bay and the mid-coastal area of Santa Barbara. This undertaking will be discussed a later presentation.

Approaches to Management and Associated Principles and Policies

As mentioned, California faced several constraints similar to China's. Lack of hydrologic data, lack of financing (no government or World Bank financing available), and certain time constraints to meet rapidly growing (but unknown) demands for all services. But California also started in 1850 with essentially ample uncommitted water resources and few people. Nevertheless, certain aspects of development and the associated evolution of institutions, policies and methodology may be informative as China grapples with its situation.

1. General structure and role of government at various levels in California (Central, state, county and city) 
a. social and economic well-being
b. land and water resources stewardship
c. services scope and financing

2. Initial obstacles to water development and the nature of actions taken
a. lack of hydrologic data
b. conflicting water development and uses
- miners vs. farmers
- riparian land owners vs. non-riparian land owners
c. no basis for water allocation
d. lack of financing irrigation infrastructure
e. inadequate service and stewardship institutions
f. increasing need for more reliable supplies to urban centers

3. From 1850 and 1900, due to the pressures from water users, California took critically important decisions. It created;
a. water rights / water allocation system tailored to the situation (in addition to the English Riparian Law). Features included;
- first in time with beneficial use, first in right serving as allocation mechanism
- rights were usufructuary for use but not ownership of the water State owns the water
- linking rights to land, but amount limited to water beneficially used.
- rights holder may not expand use to return flows
- so called irrigation inefficiencies recognized as a major source of recharge to groundwater. (Many districts do not line canals for that reason.) (irrigation sector efficiency is over 87%)
b. modified the general districts laws with a quasi-governmental form of water-related service entities with powers of taxation, (in the case of irrigation, vote based upon area and population and right-of-way condemnation powers, (This was subsequently adopted by most other Western US states),
c. modified districts' law so either beneficiaries or local government can organize to provide a range of associated services. (Irrigation, drainage, local flood control and power generation). Variations include;
- customer-owned
- special district
- county
d. modifications to allow umbrella organizations of a group of districts'
e. service charges (for most services) equated to full cost recovery by services entities with recovery through tariffs and property taxes
f. a mechanism for financing service entities
service charges; general obligation bonds guaranteed by entity's power to levy property taxes; to the extend possible, revenue bonds and recovery of costs and special assessments from customers.
g. and strong regulatory bodies water rights, safety of dams, fiduciary examination of service entities, approval of all bond issues
h. Federal / state hydrologic data collection and analysis free to all
i. consolidated all water resources management within one department, with very limited services responsibilities

4. Other fundamental features of California's water management tools
a. decisions on water supply and waste treatment projects primarily based on with and without project' and least cost (conventional economic analysis schemes for a life of 100 years or more not suitable to)
b. water use efficiency considered in context of potential recovery and reuse of return flow and seepage.
c. multiple sources of water supply for reliablity, particularly to urban centers
d. reuse of urban effluent -- early and current actions (26 urban schemes now in place with direct reuse tested in San Diego and Los Angeles. (Note source of CWP and Colorado supplies to urban customers.
e. water quality impacts considered in awarding water rights and land-use zoning
f. comprehensive reissues of the State Water Plan every five years.

5. The actions of proponents led to the key changes that advanced water resources development and management
a. Appropriative right's system (basic water rights system)
b. Wrights Act (creation of the irrigation districts)
c. Modesto and Tuolumne Irrigation Districts (the first organized under act)
d. Los Angles Aqueduct (first major transbasin supply)
e. Metropolitan Water District (typical umbrella organization)
f. California Water Project statewide service system)
g. Common characteristics of all
community leaders

6. Current responsibilities and functions of Central, State, Local government, districts and individuals in water resources management 
a. data collection
b. resources planning
c. regulatory
- rights surface and groundwater
- quality / health
- fiduciary
d. structural code and safety
e. services
- water supply
- sewerage
- storm drainage / flood control
- agricultural drainage

 


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