Area Drainage Master Planning. Erik Nilssen, Douglas County Engineer April 12, 2017

Transcription

1 Area Drainage Master Planning Erik Nilssen, Douglas County Engineer April 12, 2017

2 Serial Parceling Wildcat Subdivisions Parcel Maps - NRS General requirements; exemptions. o 1. Except as otherwise provided in this section, a person who proposes o to divide any land for transfer or development into four lots or less shall: If it anticipates, based upon duly adopted ordinances and plans, that the parcels will be used for residential, commercial or industrial purposes, may require off-site access, street alignment, surfacing and width, water quality, water supply and sewerage provisions only as necessary and consistent with the existing use of any land zoned for similar use which is within 660 feet of the proposed parcel. If the proposed parcels are less than 1 acre, the governing body or, if authorized by the governing body, the planning commission or other authorized person may require additional improvements which are reasonably necessary and consistent with the use of the land if it is developed as proposed.

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9 July 2014

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14 Douglas County Flood Damages 2014 Flash Floods Douglas County experienced four flash flood events that occurred on July 20, July 30, August 6, and August 11, o July 20 th 1.23 inches of rain in 2-hours the 100-year, 2-hour storm o August 12 th Record Courier reported 1.5 inches of rain in 15-minutes (approaching the 1000-year, 30-minute storm) $927,205 to Pubic Infrastructure $1,556,983 Damage to Private Property o 144 Lots affected 2015 Flash Floods July 6, 2016 o Paper reported.59 inches of rain in one hour in Minden (approximately 10-year, 1- hour storm) Was probably more intense in localized areas $2,213,539 Damage to Public Infrastructure State produced no damage estimate of private property

15 Drainage Patterns

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17 Berms and Diversions

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19 Great Idea #1

20 Great Idea #1

21 Great Idea #1

22 Great Idea #2

23 Great Idea #3

24 Hydrologic Cycle

25 Hydrologic Cycle

26 Area Drainage Master Plan

27 Identify Existing Drainage Patterns

28 Identify Capital Projects

29 Identify Probable Costs & Quantities

30 Preliminary Construction Drawings

31 15% Design Plans

32 Alternatives

33 Integration

34 Integration

35 Integration

36 Integration

37 Integration

38 Integration

39 Funding?

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41 Cost to Maintain

42 Stormwater Management A stormwater management program is a planned and managed process to bring complex institutional, technical, financial, political, and societal issues together to implement solutions, goals and objectives for stormwater management. o Floodplain Management (FEMA CRS) o Flood Damage Reduction o Water Quality Lake Tahoe Total Maximum Daily Load Douglas County MS4 Permit

43 Goals o Maintain existing floodplain boundaries and depth of flooding. o Keep major roadways passable in heavy storm events. o Replace aging infrastructure. o Keep water bodies healthy. o Conduct necessary maintenance of infrastructure. o Maintain appropriate and correct utilization of irrigation ditches. o Provide for drainage master planning. o Capital construction.

44 Basis of the Utility Sewer Rates Equivalent Dwelling Unit (EDU) Stormwater Equivalent Residential Unit (ERU)

45 Why A Stormwater Utility (SWU)? A SWU user fee methodology is equitable because the cost is borne by the user on the basis of the user's demand placed on the drainage system. A SWU is stable because it is not as dependent on the whims of the annual budgetary process as taxes. A SWU is adequate because a typical stormwater program can be financed with payments below what the normal customer is willing to pay. A SWU is flexible because it can be periodically adjusted along with major transitions in programs and priorities.

46 Implementation Difficulties Towns and General Improvement Districts Valley Versus Lake Agricultural Community Remuneration General Douglas County Tax Aversion Administration NOT A FLOOD PROBLEM FIX ALL

47 FIN