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.; Weed Conttrol Plan Pneblo East Pit Continental Materials (Transit Mix of Pneblo) Permit M-19$6-015 Jnly Z7, 2004 RECEIVED JUL 2 7 2U04 Division of Minerals & Geobgy Background: A weed control plan is now required for all Reclamation Permits. It has been found that although the reclamation plan for this operation contains various wording that addresses weeds that wording does not constitute a formal weed coohol plan. This weed control plan updates that requirement in the pdnmit. Weeds Present oa the Stte: A few noxious weeds and a few non-noxious weeds axe present on this site. The weed.of most concern is hoary cress, also known as Whitetop (Cardsria drabs). Also present, but of somewhat leas concern is the ubiquitous species of Tamariz-and Russian Olive, In a few locations very small sfands of Canada Thistle caa be found but this species appears to be quite sparse and not showing much sign of increasing significantly. As reclamation proceeds this latter species could become a problem. The two most troublesome ran-noxious species aro Kochia and Russian Thistle, both of which are coamtan hutnbleweeds that can present problems if growing at very big6 densities in favorable sites. Weed Controls: Whitetop will be controlled by spraying with herbicides as mechanical controls aze usually ineffective a:nd often make the problctrl worse. Tgrmtrrz is well established along the Arkansas River and in adjacent wetlands. Invasion of this spccies in reclamatioa areas will be controltcd by mechanical means, primarily cutting, plus herbicide trcatmcnt of stua>ps. Russian Olive is also comrrion in trarch of the same habitat as the Tamarrx. These two are often found growing next to each other, although. this species also occurs in higher elevation riparian forest where Tamarix is generally not present. Control methods arc the same for this species as for Tamarix, but generally cutting is a bit more effeMive with Russian Olive than with Tamarix and often herbicide treahnertt of'tlu: stumps is not necessary. Resprouting can occur, but continued mechanical removal of new sprouts&otn the sturrrp usually kills the plant. Tumbleweeds tend to be locally abundant in the old pastures and probably there is a lazge seed brink in the salvaged topsoil Moderate density popttlatioas of these specks can ottcn be of benefit to revcg'ctation by acting as a kind of cover crop, but high density populations usually prohibit the establishiiieittt of more destrable growth. It is generally a judgement call as to whether control is required and that judgement depends on many factors. When control is implemented it is usually done by mowing rather than spraying herbicides, although the latter can also be used effectively. Often two rnowings axe needed for' populations on very favorable sites, but high density poptations an less favorable sites are often killed by one spring mowing. Eventually the population declines if the soil is not re-disturbed or sufficient rrtowing is hone to reduce seed production to a low level. Thcsc species tend to have seed dormancy periods of onc~to,fmtr years and if seed production can be reduced for a few years in a row the prominence of these specter canoe reduced. Also, redisturbance of the soil tends to "reset the clock" and often generates strong growths of jklese species far a couple of years. Thexefoxt; rcdisturbance of the soil, if posstble, should be . avoided umt%I the destrable vegetarion is established. pages