HomeMy WebLinkAboutCORRESPONDENCE - PURCHASE ORDER - 9185741 (2)Scope of Work:
This scope of work includes year two of a revegetation project for the total landscaped area of
Timberline Recycle Center as shown below. Work will begin with Spring weed control (minimum one
herbicide application) as directed by a Spring walk with the Project Manager. Reseeding of non-
successful native areas (see notes below in site areas approximately 50,000 sf for estimating purposes)
will need to take place early to mid-May at a rate of a minimum of 35 to 45 pounds PLS per acre
broadcast seeding rate. Include costs for one additional herbicide treatment in July/Aug. Existing
temporary Irrigation will need to be reviewed in the Spring and some slight modifications to zones may
need to be made to ensure coverage. An irrigation schedule will be prepared (based on information
included below) for establishment of the native seed for reseeded areas. Seed germination will be
analyzed 14-21 days after seed is placed and irrigation has begun.
Weed control should be included in this scope and should include 8 hours every two weeks for two
people from May through end of August (10 occurrences at 16 hours = 160 hours). Weeds may need to
be hand pulled or spot sprayed with glyphosate depending on the condition. Contractor shall plan to
walk site with Project Manager on a monthly basis to determine best weeding methods. Weeding shall
include all of revegetation area as well as the rest of the landscape around the recycle center (shrub
beds, fence lines, etc.).
Site Areas:
North facing slope: +61,860 sf (blue): assume 15,000 sf of reseeding
South facing slope: +58,900 sf (yellow): assume 15,000 sf of reseeding
Front entry native only: 8,653 sf (orange): assume 2,000 sf of reseeding
Front entry tree area: 10,420 sf (red)
Solar area: 11,680 sf (pink) unirrigated: Assume 11,680 sf of reseeding
Future expansion area: 12,950 sf (green) unirrigated: Assume 6,000 sf of reseeding
Total Landscaped area: 164,463 sf (3.77 acres)
DocuSign Envelope ID: 4F301267-12AC-4D49-9D7E-5966D0A952C8
Seed Mix:
Bouteloua gracilis blue grama (50%); Buchloe dactyloides buffalograss (30%); Schizachyrium scoparium
little bluestem (20%); possibly Koeleria macrantha, prairie Junegrass
OR contractor recommended 40-35-15-10 mix of Buffalo Grass, Blue Gramma, Blanket Flower, Little
Bluestem mix
Seeds germinate when soil is warm. When looking at 2” soil temps, it appears most likely to hit soil
temperatures of 60-65 degrees starting after mid-May, on average. Soil temperatures:
https://ccc.atmos.colostate.edu/~autowx/fclwx_current.php
On average, seeding rates for upland areas are approximately 18-25 lbs of seed per acre for drill seeding.
Broadcast seeding rates of 35 to 45 pounds PLS per acre are adequate for most dryland broadcasting,
depending on the plant species in the mix.
Irrigation1
Monitoring of irrigation is a critical management activity that should occur if irrigation is to be used on a
site. Either too much water or too little water can be detrimental to the survival of newly planted
seedlings and plantings. Soil type will also influence the amount of irrigation needed since clay soils
require less water to remain moist than do sandy soils. Moist soils in April encourage cool season native
species to grow, whereas warm season grasses start to grow when soil is warmer with adequate
moisture in mid to late May.
In order for native seed to germinate, the top 1 to 2 inches of soil should be moist, but not saturated.
Initial irrigation should maintain moist soil in the seed bed, watering up to twice a day. Use of mulch or
landscape fabric will reduce the frequency of irrigation required to maintain surface moisture. Once the
grasses begin to establish, the roots will penetrate into the soil more deeply and irrigation should be
reduced to three or four times a week, but for a longer duration, to allow for up to 6 inches of moisture
in the soil. Irrigation should then be curtailed to one to two times per week later in the summer until the
fall months when irrigation would cease to allow the plants to harden for the winter months. Table 13-
11 provides a sample irrigation schedule for establishing native areas. Mulching/crimping/
hydromulching seeded areas is also crucial to keep moisture in the soil.
1 https://udfcd.org/wp-content/uploads/uploads/vol2%20criteria%20manual/13_Revegetation.pdf
DocuSign Envelope ID: 4F301267-12AC-4D49-9D7E-5966D0A952C8
After seeding:2
Warm season grasses are slower to germinate than cool season grasses, often taking 14-21 days before
the seedlings can be seen.
2 The Use of Native Warm Season Grasses for Critical Area Stabilization Christopher F. Miller1 and John A.
Dickerson2
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