Gross Reservoir
{{Use mdy dates|date=October 2023}}
{{Infobox body of water
| name = Gross Reservoir
| native_name =
| native_name_lang =
| image = Gross Reservoir.JPG
| alt =
| caption = The reservoir in 2014.
| image_bathymetry =
| alt_bathymetry =
| caption_bathymetry =
| location = Boulder County, Colorado
| coords = {{coord|39|56|31|N|105|22|22|W|region:US-CO_type:waterbody|display =inline,title}}
| type = reservoir
| etymology = Named for Denver Water former Chief Engineer Dwight D. Gross.Denver Water. [http://www.denverwater.org/Recreation/GrossReservoir/ Gross Reservoir]. Viewed 2014-09-22.
| inflow =
| rivers =
| outflow = South Boulder Creek
| catchment =
| basin_countries = United States
| agency = Denver Water
| designation =
| length =
| width =
| area = {{convert|440|acre|abbr=on}}
| depth =
| max-depth =
| volume = {{convert|41,811|acre.ft|abbr=on}}
| residence_time =
| shore =
| elevation = {{convert|2222|m|abbr=on}}{{cite gnis|id= 202790|name=Gross Reservoir|accessdate=2014-09-23}}
| frozen =
| islands =
| cities =
| pushpin_map = Colorado#USA
| pushpin_label_position =
| pushpin_map_alt = Location of Gross Reservoir in Colorado, USA.
| pushpin_map_caption =
| website =
| reference =
}}
Gross Reservoir, located in Boulder County, Colorado, is owned and operated by Denver Water. Completed in 1954, the reservoir has a surface area of {{convert|440|acre}}, and the spillway sits at {{convert|7,225|feet}} elevation. The reservoir is undergoing an expansion project.
The reservoir receives water from South Boulder Creek and the western side of the Continental Divide through the Moffat Tunnel. South Boulder Creek flows out of the {{convert|340|feet||adj=mid| high dam}}.
Recreation
Expansion project
The proposed expansion of Gross Reservoir would allow Denver Water to store an additional {{convert|77,000|acre feet}} of water, drawn mostly from the Fraser and Williams Fork Rivers.{{Cite news|last=Gardner-Smith|first=Brent|date=20 April 2016|title=Denver Water official says more West Slope water projects 'not on our radar'|work=Aspen Journalism|url=https://www.aspenjournalism.org/denver-water-official-says-more-west-slope-projects-unlikely/|access-date=25 November 2020}} Construction on the project, expected to be complete around 2027,{{Cite news |last=Ingram |first=Elizabeth |date=2023-07-20 |title=Why Denver Water is raising Gross Dam |url=https://www.hydroreview.com/dams-and-civil-structures/dam-design-and-construction/why-denver-water-is-raising-gross-dam/ |access-date=2023-10-21 |work=Hydro Review |language=en-US}} will raise the level of the dam by {{convert|131|ft|m|abbr=off|sp=us}}, resulting in an additional {{convert|77,000|acre.ft|abbr=off|sp=us}} of water storage capacity in the reservoir and making it the tallest dam in Colorado.{{cite news|last=Brennan|first=Charlie|date=2 January 2018|title=Denver firm awarded $13M design contract for expansion of Boulder County's Gross Reservoir|work=Boulder Daily Camera|location=Boulder, CO|url=http://www.dailycamera.com/boulder-county-news/ci_31564689/gross-reservoir-expansion-contract|access-date=25 November 2020}}
Denver Water applied to the U.S. Army Corps of Engineers for a permit under section 404 of the Clean Water Act, required to construct the expansion, and that permit was granted in 2017.{{Cite news|last=Ingram|first=Elizabeth|date=12 July 2017|title=Denver Water approved to expand reservoir behind Gross Dam|work=Hydro Review|url=https://www.hydroreview.com/2017/07/12/denver-water-approved-to-expand-reservoir-behind-gross-dam/|access-date=25 November 2020}} In response, several environmental groups sued USACE on grounds that the agency's deliberations about granting the permit violated the Clean Water Act, Endangered Species Act, and National Environmental Policy Act.{{Cite news|last=Brennan|first=Charlie|date=19 December 2018|title=Environmental groups sue to block expansion of Boulder County's Gross Reservoir|work=Boulder Daily Camera|url=https://www.dailycamera.com/2018/12/19/environmental-groups-sue-to-block-expansion-of-boulder-countys-gross-reservoir/|access-date=25 November 2020}} In July 2020 the Federal Energy Regulatory Commission granted a required modification to the Federal Power Act license granted to Colorado Water for Gross Dam before it was built.{{Cite news|last=Jones|first=Corey H.|date=17 July 2020|title=Boulder County's Gross Reservoir Can Proceed With Expansion Following Lawsuit|work=CPR News|url=https://www.cpr.org/2020/07/17/boulder-countys-gross-reservoir-can-proceed-with-expansion-following-lawsuit/|access-date=25 November 2020}}
A contract for design services was awarded to Stantec, an engineering consulting firm, in 2017.
Boulder County announced in spring 2019 that it would require Denver Water to obtain a land use permit under Colorado law before commencing the expansion project.{{Cite news|last=Lacey|first=Hank|date=24 November 2020|title=Gross Reservoir Expansion Proposal Presents Water Demand, Environmental Concerns|work=Law Week Colorado|url=https://lawweekcolorado.com/2020/11/gross-reservoir-expansion/|access-date=25 November 2020}} Denver Water submitted its application for that permit in September 2020.{{Cite news|last=Swearingen|first=Deborah|date=5 October 2020|title=County's review of proposed Gross Reservoir expansion underway|work=Boulder Daily Camera|url=https://www.dailycamera.com/2020/10/05/boulder-countys-review-of-proposed-gross-reservoir-expansion-underway/|access-date=25 November 2020}} Boulder County commissioners approved the expansion in 2021 and accepted a $12.5 million mitigation deal.{{Cite news |last=Booth |first=Michael |date=2023-10-20 |title=Forest Service says Denver Water is taking down too many trees, rushing requests to change plan to raise Gross Dam |url=http://coloradosun.com/2023/10/20/denver-water-gross-dam-expansion-forest-service-flaws/ |access-date=2023-10-21 |work=The Colorado Sun |language=en-US}}{{Cite web |title=Gross Reservoir Impact Mitigation Fund |url=https://bouldercounty.gov/departments/commissioners/gross-reservoir-mitigation-fund/ |access-date=2023-10-21 |publisher=Boulder County |language=en-US}}
Climate
The hottest temperature recorded at Gross Reservoir was {{convert|94|F|C|1}} on July 9, 2003, June 23, 2012, June 26, 2012, and June 22, 2016, while the coldest temperature recorded was {{convert|-24|F|C|1}} on February 2, 2011.
{{Weather box
|location = Gross Reservoir, Colorado, 1991–2020 normals, extremes 1978–present
|single line = Yes
|collapsed = Yes
|Jan record high F = 67
|Feb record high F = 64
|Mar record high F = 72
|Apr record high F = 78
|May record high F = 89
|Jun record high F = 94
|Jul record high F = 94
|Aug record high F = 92
|Sep record high F = 91
|Oct record high F = 81
|Nov record high F = 70
|Dec record high F = 64
|Jan avg record high F = 57.7
|Feb avg record high F = 58.1
|Mar avg record high F = 66.3
|Apr avg record high F = 72.3
|May avg record high F = 78.7
|Jun avg record high F = 88.0
|Jul avg record high F = 89.8
|Aug avg record high F = 87.7
|Sep avg record high F = 84.7
|Oct avg record high F = 75.5
|Nov avg record high F = 66.5
|Dec avg record high F = 58.1
|year avg record high F = 91.0
|Jan high F = 39.3
|Feb high F = 39.7
|Mar high F = 47.2
|Apr high F = 52.2
|May high F = 60.8
|Jun high F = 72.6
|Jul high F = 79.3
|Aug high F = 77.1
|Sep high F = 69.7
|Oct high F = 56.8
|Nov high F = 47.0
|Dec high F = 39.5
|year high F =
|Jan mean F = 28.1
|Feb mean F = 28.2
|Mar mean F = 34.7
|Apr mean F = 39.7
|May mean F = 48.1
|Jun mean F = 58.1
|Jul mean F = 64.5
|Aug mean F = 62.3
|Sep mean F = 55.2
|Oct mean F = 44.1
|Nov mean F = 35.3
|Dec mean F = 28.5
|year mean F =
|Jan low F = 16.9
|Feb low F = 16.7
|Mar low F = 22.1
|Apr low F = 27.1
|May low F = 35.4
|Jun low F = 43.6
|Jul low F = 49.6
|Aug low F = 47.6
|Sep low F = 40.6
|Oct low F = 31.3
|Nov low F = 23.5
|Dec low F = 17.5
|year low F =
|Jan avg record low F = -4.5
|Feb avg record low F = -6.1
|Mar avg record low F = 5.4
|Apr avg record low F = 13.7
|May avg record low F = 23.3
|Jun avg record low F = 35.7
|Jul avg record low F = 43.9
|Aug avg record low F = 40.0
|Sep avg record low F = 30.6
|Oct avg record low F = 15.5
|Nov avg record low F = 4.9
|Dec avg record low F = -5.2
|year avg record low F = -11.8
|Jan record low F = -13
|Feb record low F = -24
|Mar record low F = -14
|Apr record low F = 0
|May record low F = 11
|Jun record low F = 28
|Jul record low F = 35
|Aug record low F = 27
|Sep record low F = 16
|Oct record low F = -1
|Nov record low F = -14
|Dec record low F = -19
|precipitation colour = green
|Jan precipitation inch = 0.71
|Feb precipitation inch = 0.90
|Mar precipitation inch = 1.94
|Apr precipitation inch = 2.73
|May precipitation inch = 2.89
|Jun precipitation inch = 1.87
|Jul precipitation inch = 2.04
|Aug precipitation inch = 2.12
|Sep precipitation inch = 1.99
|Oct precipitation inch = 1.35
|Nov precipitation inch = 0.96
|Dec precipitation inch = 0.78
|year precipitation inch =
|unit precipitation days = 0.01 in
|Jan precipitation days = 4.7
|Feb precipitation days = 5.6
|Mar precipitation days = 6.3
|Apr precipitation days = 8.4
|May precipitation days = 10.5
|Jun precipitation days = 8.1
|Jul precipitation days = 10.2
|Aug precipitation days = 10.9
|Sep precipitation days = 7.3
|Oct precipitation days = 6.0
|Nov precipitation days = 4.9
|Dec precipitation days = 4.9
|Jan snow inch = 9.4
|Feb snow inch = 14.0
|Mar snow inch = 21.0
|Apr snow inch = 19.8
|May snow inch = 3.9
|Jun snow inch = 0.1
|Jul snow inch = 0.0
|Aug snow inch = 0.0
|Sep snow inch = 0.9
|Oct snow inch = 6.9
|Nov snow inch = 12.0
|Dec snow inch = 11.1
|year snow inch =
|unit snow days = 0.1 in
|Jan snow days = 4.0
|Feb snow days = 4.7
|Mar snow days = 4.8
|Apr snow days = 4.6
|May snow days = 1.3
|Jun snow days = 0.0
|Jul snow days = 0.0
|Aug snow days = 0.0
|Sep snow days = 0.4
|Oct snow days = 1.9
|Nov snow days = 3.8
|Dec snow days = 4.0
|Jan snow depth inch = 7.7
|Feb snow depth inch = 8.2
|Mar snow depth inch = 11.3
|Apr snow depth inch = 10.4
|May snow depth inch = 3.4
|Jun snow depth inch = 0.0
|Jul snow depth inch = 0.0
|Aug snow depth inch = 0.0
|Sep snow depth inch = 0.9
|Oct snow depth inch = 5.1
|Nov snow depth inch = 7.3
|Dec snow depth inch = 7.9
|year snow depth inch = 18.4
{{cite web
|url = https://www.ncei.noaa.gov/access/services/data/v1?dataset=normals-monthly-1991-2020&stations=USC00053629&format=pdf&dataTypes=MLY-TMAX-NORMAL,MLY-TMIN-NORMAL,MLY-TAVG-NORMAL,MLY-PRCP-NORMAL,MLY-SNOW-NORMAL
|publisher = National Oceanic and Atmospheric Administration
|title = U.S. Climate Normals Quick Access – Station: Gross RSVR, CO
|access-date = February 7, 2023
}}
|source 2 = National Weather Service
{{cite web
|url = https://www.weather.gov/wrh/climate?wfo=bou
|publisher = National Weather Service
|title = NOAA Online Weather Data – NWS Boulder/Denver
|access-date = February 7, 2023
}}
}}
See also
References
{{Reflist}}
External links
- [https://grossreservoir.org/construction/raising-a-dam/ Expansion Project official website]
- [https://www.savebouldercounty.org/ Anti-Expansion Project official website] {{Webarchive|url=https://web.archive.org/web/20210716221130/https://www.savebouldercounty.org/ |date=July 16, 2021 }}
{{authority control}}
{{DEFAULTSORT:Gross Reservoir}}
Category:Reservoirs in Colorado
Category:Protected areas of Boulder County, Colorado