for Erosion/Sedimentation* · PDF file Erosion/Sedimentation 2. Plans for erosion/sedimentation control should meet the following minimum criteria: a. During development and/or construction,

Basin Plan Amendment and Action Plan

for Erosion/Sedimentation*

Problem Statement

Accelerated erosion from man's disturbance of soil resources (construction, agri- cultural operations, highway construction, etc.) contributes to turbidity and sedimentation in basin streams. For example, the US Army Corps of Engineers removes over 10 million cubic yards of sediment yearly from the Sacramento River.

There exists a tremendous push by the urban population for construction of primary residences and second-homes (with support activities) in the rural lands of the Central Valley. Exposure of soil during construction of house pads and access roads, and the subsequent earth disturbing cuts and fills can accelerate erosion many times above that which occurs in undeveloped watershed lands.

Agricultural activities can cause a long-term persistent erosion/sedimentation problem. Conversion of steeper sloping lands for agricultural production is occurring as new water sources become available and flatter land becomes more scarce. The conversion of these lands involves the removal of natural vegetation and alteration of natural drainage patterns, which can increase erosion from irrigation and rainfall runoff.

Highway construction, management of forest lands and federal grazing lands are also sources of accelerated erosion; however, these are dealt with in other 208 issues.

Sediment from erosion can have both short and long-term effects on water quali- ty/beneficial uses. The immediate effect is increased turbidity in adjacent water ways, resulting in adverse impacts on fish and wildlife habitat, reduced water pump life due to abrasion, increased municipal/industrial water treatment costs for :turbidity removal, and impaired recreation and aesthetic value. Some of the long- term effects are reduced reservoirs capacity, increased flooding hazard from reduced channel capacities, increased irrigation system maintenance and increased dredging costs. Sediment is also a carrier of other pollutants such as pesticides, heavy metals, and nutrients.

Action Plan

The State and Regional Boards contracted with several agencies to collect existing data and make recommendations for developing a statewide policy and a regional action plan for the control of erosion/sedimentation. These studies have been completed and used as supportive studies (Attachment 1) for this Regional Board action plan.

Objective are: 1. Beneficial uses of receiving waters that are presently significantly impacted

by sediment should be restored to a water quality level consistent with state and federal water quality standards.

* As adopted in Resolution No. 79-180

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Erosion/Sedimentation

Beneficial, uses of receiving waters presently unimpaired out threatened by

impacts of sediment should be protected,

Sediment control standards and program performance evaluation criteria, should

be-bas-ed7upon-Best Management-Practices_and_upderstanding of the impacts of

sediment on beneficial uses.

A. Local units of government. should have the lead role, with the Regional Board

involving and assisting them, in the assessment'Of sediment problems,'the

determination of problem areas, and the estimate of sediment control Priori-

ties within their jurisdiction.

5. Land use activities that produce significant sediment impacts upon beneficial

uses .should' be addrested by local volUntary prOgraMS that provide for inclu-

sion of Best Management Practices.applied in the context of management plans

acceptable to the affected land'users..

6. Minimum county-wide erosion control and surface runoff management criteria

should be enacted to address impacts of sediment produced by construction.

activities.

7. Regional Board participation in sediment control programs shall include

assistance in the establishment of local control programs, participation :in

the determination of water quality problem areas and a cooperative progran

evaluation with local units of government. Upon failure of local programs to

address impacts, waste discharge permits shall be issued for sediment control

purposes.

8. In critical water quality problem areas, counties and cities in the Central

Valley should submit action plans to the Regional .Board within a reasonable

time frame that sets forth local sediment control programs consistent with

basin plan objectives and criteria. The control features of such action plans

shall be incorporated into subsequent water quality management plans.

Guidelines for Existing Erosion/Sedimentation Probelms

1. The resource management subsystem approach developed by the USDA-Soil Conser-

vation Service and reported in their "Recommended Plan.for Best Management

Practices" shall be considered as Best. Management Practices to control, or

reduce erosion/sedimentation.

2. The Regional Board recognizes the sediment problem area maps developed by the

USDA-Soil Conservation Service as the most comprehensive regional assessment

of erosion problems for private lands presently available. These maps will be

refined to assess significantly impacted water with the. ehlp of SCSLRCD,

county, and interested agencies.

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Erosion/Sedimentation -3-

3. Regional Board will cooperate with counties to establish county erosion control.committees, composed of interest groups including those representing the public interest, and local, state, and federal agencies with resource management skills, Committee_duties _are:

a. Provide local input and assistance to develop a control plan for the problem area.

b. Define with the Regional Board, seasonal water quality and soil loss standards for their area.

o. Seek technical assistance from agencies in planning, review, and tnplemen- tation of Best Management Practices..

d. Seek funding for implementation of Best Management Practices.

e. Provide leadership In working with land users-An the problem area.

f. Encourage development and/or implementation of local erosion/sedimentation control ordinance.

Guidelines for Potential Erosion/Sediment Problems

A. Agriculture

Potential problems stem from conversion of one type of agricultural: land use to another (i.e., range to Oultivated'agriculture) which result in soil disturbing activities and removal of vegetative cover.

1. Local units of government should identify areas where such conversions are likely. to occur and erosion/sedimentation will have adverse impaCts on water duality.

2. The county erosion control committees should work with the County to develop a Control plan for identified areas.

3. Local USDA-Soil Conservation Service/RCD and DC Cooperative Extension Offices should establish education and information. programs to assist agricultural land users in planning and applying Best 4apagement.PracticeS to mitigate erosion during. And after conversion.

B. Construction

1. Plans .for erosion/sedimentation control should be a requirement for' issuance.Of a county or city grading and/or building_ permit for construc- tion activities that will disturb greater. than 10,000 square feet of surface area and/or more than 100 cubic yards of excavated material.

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Erosion/Sedimentation

2. Plans for erosion/sedimentation control should meet the following minimum

criteria:

a. During development and/or construction, adequate measures to protect against erosion/sedimentation shall be provided.

b. Land shall be developed in increments of workable size that can be

completed during a single construction season. Emsion and sediment control measures shall be coordinated with the sequence of grading,

development and construction operations.

c. Vegetation shall be removed only when absolutely necessary.

d. Every effort shall be made to conserve top soil for reuse in revegeta-

tion of disturbed areas.

e. All disturbed soil surfaces shall be stabilized and revegetated before

the rainy season.

In addition, plans should address the need for the following criteria:

a. Sediment basins and traps shall be installed in conjunction with the initial grading operation.

b. The drainage, and storm water runoff control system and its component facilities shall be designed to fit the hydrology of the area under full, development and have adequate capacity to transport the flow from

all upstream areas.

c. The drainage and storm water runoff control system and its component facilities shall be nonerosive in design, shall conduct runoff to a stable outlet, and be installed prior to the rainy season.

3. Those counties and cities that have adopted and are implementing ordinances and programs compatible with these guidelines shall transmit tentative maps fOr land develpments containing 100 lots or more with sufficient informa- tion that the proposed development will meet these guidelines or the approved county/city erosion control ordinances.

4. Construction activities in counties and cities having no erosion control programs or one which is not in compliance with the Regional Board guide-

lines may be required to file a report of waste discharge.

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.--Erdsion/Sedimentation

Supportive Studies

The following studies tional information on

1. Recommended Plan 1979.

2. 208 Institutional

were performed to provide mu