Black Gore Creek Total Maximum Daily Load Sediment Source Monitoring 2007 Vail Pass, Colorado

Transcription

1 Black ore Creek Total Maximum Daily Load Sediment Source Monitoring 2007 Vail Pass, Colorado The photograph above shows the Black ore Creek channel at Mile Marker Prepared for: Eagle River Watershed Council Prepared by: RiverRestoraiton.org

2 I. Introduction This document presents data results that were collected to support the Black ore Creek TMDL sediment source monitoring. Other simultaneous efforts are underway to monitor in channel sediment sizes and biologic indicators of stream health. Data collection and analyses herein represent the fourth annual sediment source monitoring effort. II. Methods Field data collection was conducted by RiverRestoration.org from September 27-October 16, Two snow storm events occurred during the monitoring period. Monitoring efforts were not conducted during these storm events, however monitoring was conducted during the associated melt and transport events. Eight sediment source categories were monitored, these include: Erosion Control Basins (ECB); ullies (); Valley Floors (VF); Photo Monitoring (PM); Bridge accumulation (BR); Center Median (CM); Cut Slopes (CS); and Fill Slopes (FS). A detailed description of sediment source monitoring procedures is in the BC Sediment Source Monitoring Field uide (Total Maximum Daily Load, 2007). In addition to annual sediment source monitoring, a longitudinal profile and cross sections survey at MM 186.5, as well as an inventory of culverts was conducted. The mileage stationing used to identify reference points and locations were based on aerial photographs (digitized in 2006), as well as CDOT bench marks and Interstate-70 mile markers along the highway. Reference points may vary 0.1 mile. Aerial photographs were brought into the field and utilized to map detail such as: reference points, BMP locations and type, culvert locations, gullies and concentrated drainage, areas of exacerbated native erosion, exacerbated bank erosion, and other information that may be helpful to monitor sediment transport within the Watershed. Photographic Monitoring (PM) reference points were revisited where they were set in The reference point at had been removed from traffic or plow activity, and there were no CDOT B&C reference points at and Photographs were taken from an approximate location. Photographic Monitoring reference points should be re-established at 184.5, and during the next monitoring effort. Erosion Control Basins (ECB), ullies (FS), Valley Floors (VF) and Center Medians (CM) were monitored with level surveys of cross sections or profiles from established benchmarks. Disturbed Tag Line Posts (TLPs) observed in 2007 were re-established with elevations turned from the associated benchmark. Common causes of the disturbed TLPs are from snow creep, soil creep, and hill slope slumping. The TLPs that need to have new elevation established are at: ully LEP #1, LEP#3, REP #1, REP, REP, and WTP #1. Fill Slope (FS) rill density was measured at the top of the slope. Vegetative cover percentages on the FS were based on visual estimates. Slope angles were estimated in 2004 with an inclinometer. 1

3 Cut Slopes (CS) monitoring was performed at all CS to verify if sediment controls, such as sediment basins installed by CDOT, appeared adequate. The distance of a CS was a measure between a culvert (or direct stream input) and the nearest upstream adequate sediment control. Cut Slopes upstream of Black Lakes were not monitored because all sediments transported are currently being retained by Black Lakes. The spillway of Black Lake no.2 was visually monitored for sediments to indicate transport from Black Lakes into Black ore Creek. Bridge Accumulation (BA) and Valley Floors (VF) were monitored by single depth measurements. Single depth measurements were monitored with a sediment probe at a reference post. A Culvert Inventory was conducted in 2006 and This effort is not part of the budget calculation or required for annual source monitoring. The inventory was intended to be used to document the highway drainage to outside of the highway corridor, and inventory the condition of these culverts. Culverts that are not maintained may lead to gullies significantly eroding the fill slopes, as well as large delta deposits in Black ore Creek. The maps provided in the Black ore Creek Sediment and Chemical Deicer (Lorch, 1998), and aerial maps were utilized to locate the culverts. III. Results Photographic Monitoring Table 1 summarizes the evident changes in the PM data between 2004 and Table 1 Photographic Monitoring Summary Reference Photo 9/13-9/14-9/14- Point Description 9/17 9/15 9/29 PM Confluence WTP #2 LEP WTP #1 LEP CDOT BM Towards US BC and confluence with ore Creek Towards WTP #2 REP Towards WTP #1 REP Towards East and center median I JP 011.JP 012.JP 031.JP 2006/pi cs/im P \pi cs\im P \pi cs\im P \IM P /27-10/16 Observations More dense vegetation on deposits at downstream end of island. More dense vegetation growth from Newly paved road in The side channel (behind dead tree 2005) has been abandoned and vegetated in photo shows channel braiding and large lateral bar. Dense vegetation growth from on lateral bar. Increased willows and bank stability. Paved road in More dense vegetation growth in center median. There are some invasive weeds. Erosion control logs are buried with sediments and vegetation has successfully established approximately 70% cover. 2

4 ECB REP ECB #2 LEP ECB #1 LEP PM Towards ECB LEP Towards ECB #2 REP Towards ECB #1 REP Towards westbound I- 70 fill slope JP 035.JP 036.JP 034.JP 09-26\IM P \IM P \IM P \IM P Photographs show there is a deposition trend (x-sec surveys shows trend also). Vegetation is establishing on deposits, and channels are cutting through the deposits. Photographs shows sediments depositing behind beaver dams. Note the island growth and increased cover of vegetation. Crosssections show deposition trend of approximately 0.50 feet from 2004 to Vegetation appears smothered from deposition between 2004 and No change of fill slope. ood vegetation cover and no slumping or uncontrolled stormwater is evident. Photographs may show growth of sediment deposits in the channel impoundment. Note in 2004 the water surface was 0.3 feet higher than PM BR PM PM Towards DS BC, 180 US mm183.5 From near BR towards E. abutment S. wing wall east bound I-70 Stand approximately 20 D/S from gage station. From Center of channel look upstream towards gage station pipe. Towards east bound I-70 fill slope JP 015.JP 017.JP 10-03\IM P \IM P \IM P \IM P Photographs show no noticeable change. Slight widening from left bank failure ( front left of photographs). There is some sand size deposits. Note the deposits on right toe, photo Photographs show rilling and transport of deposits. Photographs from show rills are filling in with deposits and some vegetation has established. Established Fines over cobble present in No deposition in Disturbed PM, no B&C in Shoulder was recently paved during 2006 monitoring. Rills have grown larger and deeper at top of fill slope. Some rills are linked together and forming concentrated drainage down fill slope. 3

5 BR BR PM PM #3 LEP PM Towards east abutment east bound I-70 Towards south pier east bound I-70 Towards east and westbound I- 70 at cut slope ditch Towards eastbound I- 70 fill slope Towards #1 REP From CDOT BM towards West and fill slope JP 030.JP 010.JP 062.JP \IM P \IM P \IM P \IM P \IM P \IM P The 2006 photograph appears to be taken from slightly different angle. There may be increased buried vegetation. Field notes commented that there are buried silt fences under abutment. Deep deposits were noted in Polk Creek from sidecast (Photo1995). Deposits were at monitoring post (Photo 2074) in Photo 2000 shows line of sidecast buildup and 2001 example of gully transporting sidecast material down from ECBs under Bridge. Photograph from 2006 appears to be zoomed in and taken from north side of post, not behind post; resulting to inconclusive PM comparison. Recently paved shoulder. Field notes document freeze/thaw weathering and slope mass failure (large chunks of debris). Uncontrolled stormwater, rilling at top of fill slope. Field notes indicated increased bank erosion Photographs show gully erosion (x-section shows erosion) with delta forming at toe. Increased bank erosion along this reach (notice background of photos). Rilling at top of fill slope. Increase in side cast deposits down fill slope and smothering of vegetation. No BM in 2007, photograph taken at approximate location. VF #3 LEP Towards US flow line and deposit Towards #2 REP JP 2006\pi cs\im P \IM P More vegetation growth has established. A large delta has formed and the elevation is now high enough that flow runs to the north of the deposit. The culvert at is source to VF Photograph 1997 is of the delta fan approximately 40 feet upstream from the monitoring post, taken in 2007 during a transport event. Photographs show right bank erosion (boulder in gully shows erosion). The delta has extended at the valley floor. 4

6 PM Towards downstream BC and natural right bank erosion JP 09-26\IM P Photographs show no change of slope. Photographs between 2006 shows deposition in the stream most likely from breached beaver dam upstream. Photograph in 2007 shows these fine deposits have been transported. PM VF #2 REP VF #1 REP Towards East looking at westbound cut slope ditch Towards VF #2 LEP Towards VF #1 LEP JP 10-03\IM P \IM P \IM P JP \IM P2065. Paved shoulder and two subsurface ECB were installed in Photograph 2071 shows subsurface basin full in Sediments transport through culvert to VF (See Capital Project Valley Floor Stabilization Other End of the Pipe report). Photograph Monitoring in 2007 shows subsurface basins are clean and shoulders have been swept. In 2006, crib walls were constructed to stabilize valley floor delta deposits from future transport. In 2007, very sparse vegetation had been established on the stabilized bank. Project site may need additional seeding to increase vegetation growth. Cross logs were installed in 2006 to dissipate energy and trap sediments. Photograph in 2007 shows erosion under the cross logs and degradation. Note: the upper gully cross logs have filled in with sediments and functioning as grade control. PM LEP Towards eastbound US- 6 grade and significant slope erosion Towards DS flow line gully and bike path JP 021.JP 10-03\IM P \IM P Vegetation growth (more dense grasses and pine sapling growth). Right bank mass wasting. Photograph 2167 (2006), and 2112 (2007) is looking up gully; note that previous erosion control measures are buried (landscape fabric, coir logs). 5

7 PM Towards upstream Black ore Creek JP 10-03\IM P Snow covered during 2006 monitoring. Site was potential capital project in In spring of 2006 the beaver dam blew out and sediments have transported downstream. In 2007 there are no notable changes. PM PM From edge of pavement bike path towards flow line gully and BC From CDOT BM towards West and median JP 028.JP 10-03\IM P \IM P No TLP reference post, and snow covered during 2006 monitoring. Photographs may show slight gully widening. Photograph 024 taken in 2005, 2182 taken in 2006, shows right bank gully erosion and increased deposits in BC. Increased sheet flow (rill growth) and smothered vegetation on westbound side of median. Cross Section Monitoring Monitoring observations are presented in Table 2 for surveyed cross sections. Cross section monitoring conducted at Erosion Control Basins show sedimentation. Fill Slope ullies show transport through the watershed. The average degradation at Fill Slope ullies is used in calculating the sediment budget. These Fill Slope ullies have formed from dilapidated culverts down Fill Slopes. Figures 1-14 show the surveyed cross sections followed by a brief description. 6

8 Figure 1 Waste Water Treatment Plant Cross Section #1 WTP # Figure 1: Waste Water Treatment Plant #1 is a cross section survey of the Black ore Creek channel upstream of the ore Creek confluence. The Black ore Creek channel is between stations 30 and 50, a cobble bar is between stations 50 and 70, and a side channel is between stations 70 and 90. The Black ore Creek channel is beginning to braid in this section. Cross section shows a degradation trend. The left reference post was bent in 2007 and a new elevation was established. Figure 2 Waste Water Treatment Plant Cross Section #2 WTP # Figure 2: Waste Water Treatment Plant #2 is a cross section of the Black ore Creek channel. The Black ore Creek channel is between stations 30 and 70; an island with flow through channels is between stations 70 and 160. In 2005 a beaver dam was constructed in the main channel, this created deposition in the main channel and scour of the island deposits. In 2006 the beaver dam had washed away; the channel scoured to a new elevation and deposition raised the island elevation. In 2007 the cross section shows some deposition in the main channel and shifting of the island deposits. 7

9 Figure 3 Erosion Control Basin Cross Section ECB Figure 3: Cross Section shows aggradation trend and more developed flow channels. Flow through channels indicates sediments transport through the basin. Figure 4 Erosion Control Basin Cross Section #1 ECB # Figure 4: Erosion Control Basin #1 is located in the Black ore Creek channel at the in-channel pond. The in-channel pond serves as a sediment basin. The left side of the channel is a sandy lateral bar. Beavers have built dams that trap these sediments and create bar deposits. The cross section shows approximately 0.5 feet of aggradation from Depth probes taken in 2007 showed up to 11 feet of deposition on the lateral bar. 8

10 Figure 5 Erosion Control Basin Cross Section #2 ECB # Figure 5: Erosion Control Basin #2 is located in the Black ore Creek channel at the in-channel pond. There is an island with flow through channels at the island. There are two channel on both sides of the island. Beavers have built dams that trap sediments and created the island. The cross section shows approximately 0.5 feet of aggradation from Depth probes taken in 2007 showed deposition greater than 15 feet deep on the island. Note: ECB is planned for sediments removal in summer of Figure 6 Fill Slope ully Cross Section # # Figure 6: Cross section #1 is at the bottom of the Fill Slope ully located at mile marker The total gully length is approximately 300 feet. Two defined rills are developing channels on the fill slope; at station 15 and at station 45. The top of the left bank has eroded and filled in the left side of the channel. From , the right bank has eroded approximately 1.0 foot. The 2005 survey does not have surveyed points at the top of the bank. Note: the left post is bent and moving with hill slope slumping, new elevations were established in 2005 and 2006; in 2007 the post held the same elevation as Control was established from the right post and the control posts at the upstream cross section. 9

11 Figure 7 Fill Slope ully Cross Section # # Figure 7: Cross Section #2 is located in the middle of the Fill Slope gully at There is a dilapidated corrugated metal pipe at station 19. In 2005 the toe of the channel was eroding on the left side of the pipe. In 2006 deposition filled in the left toe of the gully. In 2007 the cross section shows left bank erosion and deposition in the channel. From the approximate degradation was 0.2 ft 2. The right bank has eroded approximately 1.0 foot from Figure 8 Fill Slope ully Cross Section # # Figure 8: Cross Section #3 is located near the top of the Fill Slope ully at mile marker In 2004 a pipe was surveyed at station 16, this pipe was washed away in In 2005 the left post had been disturbed and a new elevation was established. A rill is developing a channel at station 5. The cross section shows sediments transport with deposition on the left bank and scour of the right. From the approximate degradation was 4.2 ft 2. 10

12 Figure 9 Fill Slope ully # # Figure 9: Cross Section 187.1#1 is located near the bottom of the Fill Slope ully. The total gully length is approximately 220 feet long. The cross section shows hill slope slumping and developed rills at stations 10 and 110. The cross section shows a degradation trend of the gully. From there was right bank failure that filled in the right toe; the approximate degradation was 6.2 ft 2. Figure 10 Fill Slope ully # # Figure 10: Cross Section 187.1#2 is located in the middle of the Fill Slope ully. The cross section shows channel widening and left and right bank failure. From the degradation was 21.7 ft 2. Note: right post was bent in 2006, a new elevation has been established. 11

13 Figure 11 Fill Slope ully 187.1# # Figure 11: Cross Section 187.1#3 is located near the top of the Fill Slope ully. From the cross section shows an approximate degradation of 4.4 ft 2. Figure 12 Cross Section #1 Valley Floor Vally Floor ully Cross Section Elevation As Built Station Figure 12: Cross Section 187.5#1 is of the gully on the middle bench of the Valley Floor. Restoration of the gully in 2006 was constructed to stabilize the valley floor delta deposits. Approximate degradation from was 3.2 ft 2 ; cross section shows scour in center and left bank. 12

14 Figure 13 Cross Section 187.5#2 Valley Floor Valley Floor ully Cross Section Elevation Station As Built 2007 Figure 13: Cross Section #1 is the gully located near the culvert outflow on the upper bench of the valley floor delta deposit. Restoration in 2006 was constructed to stabilize the delta deposits behind crib walls. Stations located between shows the crib wall deposits. Approximate degradation from was 9.3 ft 2 at the right toe to the centerline of the channel. Figure 14 Cross Section Fill Slope ully Figure 14: Cross Section Fill Slope ully shows left bank failure filling in the toe of the channel. The right bank shows erosion. From the approximate degradation was 24.3 ft 2. Note: the right post is bent and slumping and needs to be replaced, new elevations were established in 2006 and Control was performed from the CDOT BM and the left post. 13

15 Table 2 Fill Slope ullies Approximate Degradation Cross Section Degradation of Left Third (ft 2 ) Degradation of Center Third (ft 2 ) Degradation of Right Third (ft 2 ) Approximate Degradation (ft 2 ) # # # # # # VF # Notes From cross section shows left bank filling and right bank eroding. No change from Cross section shows gully widening and fill in middle of channel. Degradation at rills at the top of the gully on the Fill Slope. Cross sections show there may be hill slope slumping with rill development down the slope and continually sloping TLPs. Mass wasting of banks, in 2007, CMP eroded on both sides, significant widening of channel. Cross section shows hill slope slumping with minor degradation at the head of the gully. Significant right bank failure. Restoration efforts conducted in Approximately 70% vegetation cover has been established on the construction access, however sparse vegetation has been established on the upper delta crib wall and seeded fabric bank. The right toe of gully cribwall is undercutting to center of channel. Sediment have filled to top of cross logs at 14

16 grade. VF # Average Degradation 8.2 Scour has occurred under the cross logs that were installed in 06 restoration efforts. ood vegetation growth on construction access between upper and lower cribwalls. There is a new delta forming in channel. The lower cribwall is stable with good willow growth at toe. 15

17 Longitudinal profile and Cross sections at MM In 2004, the Forest Service performed cross section, longitudinal profile and sediment size monitoring of the Black ore Creek channel at MM In 2005, monitoring efforts discontinued because beavers built a dam that trapped large sediment deposits. In 2006 and 2007, RiverRestoration.org performed cross section and a longitudinal profile. Cross sections #1 and #2 show approximately 1.5 channel aggradation upstream of the beaver dam; cross section #3 is downstream of the beaver dam which also shows aggradation. Figures show the monitored cross sections. Figure 15 Cross Section #1 at Active Beaver Dam Reach BC x sec#1 elevation (ft) station (ft) 2004 USFS 2006 RR.org 2007 RR.org Figure 16 Cross Section #2 at Active Beaver Dam Reach BC x sec# elevation (ft) USFS 2006 RR.org 2007 RR.org -3.5 station (ft) 16

18 Figure 17 Cross Section #3 at Active Beaver Dam Reach BC x sec #3 elevation (ft) station (ft) 2004 USFS 2006 RR.org 2007 RR.org Single Depth Monitoring Monitoring points that required a single depth measurement, Valley floors (VF) and Bridge Accumulation (BR), are presented in Table 3. Deposits at the monitoring posts indicate transport of sediments through the Valley Floors and Bridges. Most of the accumulation under bridges appears to be from sidecast material. This material accumulates over time, and develops rills that transport deposits though the watershed. Most of the sediments at valley floors are supplied from culverts. Valley Floors that do not have sediments posts are identified in the budget, but at this time these valley floors are considered to not be contributing sediments because there is no visual evidence of sediments transporting from these delta deposits. Additional monitoring posts may be established in the future. Table 3 Single Measurement Reference Points Monitoring Reference Point Concurrent Deposits at Reference 2004 Depth of Deposit (ft) 2005 Deposits /TLP (feet) 2006 Deposits/ TLP (feet) VF No 0 0/4.2 0/4.2 0/ Deposits/ TLP (feet) VF No 0 0 0/3.94 0/3.94 Change in Deposits (feet)/ Notes Not at TLP, however deposits are noted 1.5 upgradient of the post. Three delta deposits are accumulating at toe of FS upgradient of this VF. No, however there are visual indicators of transport from the bench. 17

19 VF Yes / /1.6 Deposits are at post; active transport event occurred during 2007 monitoring. Flow channel is shifting to the right side of valley floor delta deposit, through the willows at the toe of fill slope. Photo 1997, 1990 BR Yes 3 0.8/ / /3.35 Sediments at post in Significant side-cast accumulation and rills are under bridge. Depth probes of sidecast material over 3 deep. BR Yes / / / 3.3 Yes, photo 2072 BR Yes / /3.5 Yes, monitoring post shows no net change in elevation; however observations note sediments at post. 18

20 Center Medians Four Center Median (CM) profiles are presented in Table 4. In 2004, these monitoring sites had evidence of sediments transporting into the culverts that drain the medians. These sites were randomly chosen to represent all center median areas. In 2007, all CM showed deposits at invert as well as deposits 10 and 30 feet upstream. Table 4 Center Median Monitoring Center Median Concurrent Deposits at Invert 2004 Deposit Depth 10 /30 Upstream (feet) 2005 Deposit Depth 10 /30 Upstream (feet) 2006 Deposit Depth 10 /30' Upstream (feet) 2007 Deposit Depth 10 /30' Upstream (feet) CM Yes 2.0/ / / /0.95 CM Yes 0.5/ / / /0.85 CM Yes 1.0/ / /0.5 CM No 0.5/ / / /0.36 Overall Change/Notes Deposits at invert 0.5. Survey shows change in deposition indicating sediment transport through system. Rilling around drainage tile that feeds to culvert. Coir logs in place u/s invert 15, 35, 50 are buried with sediments (note in 2006 these were ½ buried). Moderate vegetation 70%; mostly aster and wheatgrass with some weeds. Photographs (06), (07) Deposits on inlet (sand). Survey shows deposits transporting through system. 0.5 deposits on top of concrete with vegetation growth. No deposits at invert during 2007 survey. Fill Slope Monitoring Table 5 presents observations made at fill slopes (FS). Slope grades were measured in Sediment laden snow side-cast is most likely the significant source of sediments on the fill slopes. Large pieces of asphalt found near the toe of fill slopes was taken as evidence of snow transporting materials down slopes, in addition to fluvial transport of finer materials. Sheet flow down the fill slopes would likely not transport the large pieces of asphalt; however sheet flow develops rills and concentrates flow that is effective at transporting sand size sediments. Most 19

21 jersey barriers are effective at controlling sheet flow and routing flow to concentrated drainages down culverts. However, there are some that have eroded at the toe and are no longer effective, with flow passing under the barriers. Table 5 Fill Slope Monitoring 2004 Rills per 25 feet/ Vegetation Cover % 2005 Rills per 25 feet/ Vegetation Cover % 2006 Rills per 25 feet/ Vegetation Cover % 2007 Rills per 25 feet/ Vegetation Cover % Slope Fill Slope rade % Change from Previous Year FS WB /70 0/75 0/70 0/70 N/C FS WB Decrease in vegetation cover /100 0/100 0/90 2/60 and rill establishment. FS WB Side cast build-up smothering /100 0/100 0/90 0/70 vegetation cover. FS WB Side cast build-up smothering /100 0/90 0/90 0/70 vegetation cover. FS WB /70 0/70 0/70 0/60 FS EB /70 5/70 3/65 3/65 FS EB /90 4/90 5/70 2/60 FS EB /80 4/80 15/60 9/80 FS EB /90 4/70 6/75 4/70 FS EB /90 8/60 5/70 7/70 N/C Jersey barrier. Swale and ECB at catches sediment upstream of Bridge. Recently graded at top of fill slope. However there are three large rills (forming channels) transporting significant deposits at the toe 2075,1985. Vegetation cover is dominated by thistle and cheatgrass. Fill slope extends from Recently graded. Vegetation on slope is dominant thistle and cheatgrass. Large rills from bikepath to channel has caused slope mass failure photos taken in photos taken in , 2035 show rills are forming gully. Site is recommended for future monitoring. Well defined deep rills concentrate storm flow. 20

22 FS EB /60 8/70 7/65 6/70 N/C FS EB /90 8/70 12/70 12/70 N/C FS EB /70 8/70 12/70 4/70 Freshly graded 2221, rill development beyond graded shoulder and edge of pavement down fill slope. Large rills forming two gullies at top of slope 2219, Fill slope rill developing under jersey barrier FS EB /80 5/80 8/65 6/70 FS EB /90 0/90 2/70 5/70 Increased rilling. FS EB /100 2/90 7/65 8/65 FS EB ully Formation/ 20 ully Formation/30 ully Formation/30 ully Formation/ 30 Above fill slope adjacent to I- 70, jersey barrier has significant side cast with rill development and two gullies behind it. Large bike path swale at toe of slope, sediments transported are controlled by bikepath swale ECB Sediments deposits behind jersey barrier are almost to top of barrier (barrier extents is ). ully formation with most vegetation buried by side cast. 21

23 Cut Slope Monitoring Table 6 presents Cut Slope (CS) monitoring findings. These observations recognize where sediments from cut slopes have adequate BMP basins, controls in place, or overflowing basins. Most erosion control basins were clean in Approximately 2.5 miles of Cut Slopes were uncontrolled in Table 6 Cut Slope Monitoring Cut Slope Distance to upstream control (mile) Culvert Sedimentation Notes Two small ECBs A&B are small but clean ( ). Most drainage occurs down shoulder to culvert at Shoulder was regraded and Erosion Control logs were in place in 2007 (2051- in background). Two culverts drain west bound runoff to two CS- ECB at 182.2, cross sections show aggradation; however EB Yes 1.0 no ECBs have adequate storage. CS- ECB (2007) and (2000) are clean. Two culverts EB Yes 0.44 no drain east bound shoulder. CS no 0.3 no CS EB 183.3/ yes Reverse drainage from EB cut slope from 182.9, also drainage from shoulder downstream of EB183.3 culvert. ECB clean, potential revegeation site for Sediment removal project water at surface during monitoring ECB at is not maintained, photos 2011, This ECB is full and overflowing sediments at culvert invert. CS EB Yes Culvert 2014 no ECB. 22

24 CS WB yes CS WB no CS EB yes CS WB yes CS EB no CS WB 186.5/186.7/ no CS WB yes CS EB yes CS WB 187.5/ yes CS WB yes CS WB 188.7/188.73/ no No ECB, culvert drains wb shoulder down fill slope. ECB at clean 2184, ECB clean 2183 ECB full Upstream control at ECB clean ECB clean 2182, ECB clean 2181, full 2180, Culverts at 186 and Upstream control at ECB is small and full, however ECB is clean with adequate storage. Culvert drains downstream subsurface half full, subsurface clean 2176, clean 2175, clean small storage capaicty full ECB 2169, clean 2167, clean 2166 ECB at is full and overflowing to culvert at (2048). Drainage downstream controlled by ECB two subsurface basins are clean, subsurface full 2162, small but clean 2161, full. (uncontrolled for 0.05miles between basin and culvert ). Reverse drainage to native basin and ECB Culvert at heavy sedimentation ECB clean. Sand storage outside shed 60'x6' should be stored inside shed. 23

25 I-70 Shoulder Erosion Control Basins Erosion Control Basins that do not have cut slope ditches are also monitored. Below is a list of ECBs that control I-70 shoulders. WB: , clean, photo 2195 WB: , full, photo 2191 WB: 184.4, clean, photo 2186 WB: 185.2, clean WB: A, full & B clean, photos 2185, EB: 184.9, clean, photo 2070 EB: , full EB: , clean, photos EB: 187.2, clean, photos 2047 EB: , clean EB: , clean Bike Path Swale Monitoring Table 7 present the bike path swale monitoring results. Bike path swales are monitored similar to cut slopes. The condition of Erosion Control Basins and uncontrolled stormwater are monitored. Table 7 Bike Path Swale Monitoring Bike Path Swale Culvert Distance to upstream control (mile) Sedimentation Notes , 186.1, , 0.55 yes Uncontrolled , ECB clean with adequate storage yes Uncontrolled ; does not catch BPS drainage. Stormwater goes through culvert down FS to VF EB ECB full but flows to BPS with good storage. 2105, 2106, 2107, ECB at good storage. 2039, no no BPS ECB near full, ,188.1, 188.2, yes No ECB between and

26 Culvert Inventory Table 8 provides the approximate location, condition, and photograph of culverts inventoried. These culverts were below Black Lakes no. 2. Not all culverts may have been recovered and inventoried. Table 8 Culvert Inventory Mile Marker Diameter (inches) Condition Sediments Sediments Notes Photograph ood no Drains EB and WB shoulders and at CM? Corrugated metal pipe with grate , 4048 cm culvert shows transport photos yes ood no ood yes yes no yes Drains EB stormwater. Upstream ECB #30 adequate. Drains EB stormwater and natural gully. 2097, 2098, Upstream ECB full. Corrugated metal 2099, pipe. 2069(07) drains EB cut slope, forming gully down fill slope 2194 forest service weather station drains native and cut slope, moderate seds at invert yes sediments at invert but good veg traps ood no yes Drains EB stormwater, reverse flow and natural gully at Corrugated metal pipe yes outlet some seds 4'' ood no no Drains EB stormwater, reverse flow and natural gully at invert. Corrugated metal pipe with grate yes drains to native gully clogged with sediemnts 0.5' 2069, ood no Drains EB and bike path stormwater drains native gully Moderate no no Drains EB stormwater into ECB Failing (hole) at invert of culvert. Corrugated metal pipe Moderate no yes Poor yes yes Drains WB stormwater. Outlet at toe of fill slope. Drains WB stormwater. Corrugated metal culvert disconnected at outlet. ully starting to occur with delta deposit in BC. Hill lsope slumping 2130, 2179, (07) 2134, (07) 25

27 ood no Poor yes Drains to toe of fill slope, erosion at outlet Drains WB stormwater. Corrugated metal pipe blown out. ully forming with LWD. 0.5' sediments source to downstream beaver dam , erosion at outlet 2104, 2105, heavy sedimentation down native gully forming delta ood no Drains to toe of fill slope Poor yes Drains WB stormwater. Corrugated metal pipe is blowout. Significant gully erosion. Monitoring site. Seds ar outlet are 8.5'' 2104 invert Poor yes Drains EB and bike path stormwater. Corrugated metal pipe disconnected. ully forming down fill slope , Moderate no Drains natural WB gully. ully erosion. Erosion control logs placed upstream of culvert are buried with sediments. No deposits at invert. 2093, Drains between basins 87.0 and Moderate yes no Drains WB stormwater. Upstream ECB was full in 2006 but clean in Erosion control logs placed around invert are buried. 2106, 2148, Poor yes ood yes Moderate yes yes Moderate no Drains bike path swale. Disconnected at downstream end. Significant gully erosion. Monitoring site Drains EB stormwater. Erosion down fill slope to Bikepath swale. Upstream ECB is full, deposits at invert 3.5''. Drains to bike path swale controlled by ECB #41. Plastic pipe. 2152, drains at toe FS. (07) Drains EB stormwater to bike path swale controlled by ECB #41. Corrugated metal pipe 1/3 full of deposits at outlet Drains WB cut slope. Culvert source to Valley Floor Stormwater flows into gabion to prevent gully degradation. Flow has routed around gabion causing further gully degradation. Corrugated metal pipe ~5' west of larger pipe. 2153,

28 Moderate no Poor yes yes Poor yes Poor yes ood yes yes ood no Moderate yes Poor yes Stormwater flows into gabion to prevent gully degradation. Flow has routed around gabion causing further gully degradation. Corrugated metal pipe. 2153, 2154, 2155 Abandoned corrugated metal culvert. Near upper bench cribwall VF stabilization capital project, Culvert clogged with sediments. ully erosion 2156 Corrugated metal pipe with gully forming at outlet. Monitoring site and capital project VF stabilization, Corrugated metal pipe blown out with significant gully erosion. Failed gabions and fabric wraps in gully channel. Drains to ECB #43 bike path swale control, full. 2167, 2168 Drains EB shoulder. Unpaved shoulder upstream, and paved shoulder downstream. 2003, 2004 Drains I-70 under bike path to well vegetated slope (willows), slight gully forming Drains EB stormwater. Flow runs under culvert and drains to bike path swale and ECB #43, overflowing Swale is full and flow runs over path transporting sediments down natural slope. Natural slope gullying process is occurring from concentrated stormwater runoff. 2058, 2059 Drains I-70 under bike path to BC. Corrugated metal culvert is blown out with gully formation and headcut into the bike path. 2056, ood no Drains I-70 under bike path to BC Poor yes Drains under bike path to BC. Corrugated metal culvert. ully forming and starting to headcut into culvert Poor yes moderate yes yes Culvert is clogged, flow runs under culvert and drains to uncontrolled bike path swale. Erosion at outlet Drains WB stormwater. Upstream ECB adequate. Deposits at invert are 0.5' deep. Corrugated metal pipe set subgrade with grate. 2054, 2055, , 2158 (07) ood no yes Drains EB stormwater to rocked gully that drains to bike path swale

29 Poor yes yes Poor yes Poor yes Drains under bike path to BC. Invert looks good, outlet is buried. ully forming between bike path and BC. 2176, 2177, 2157(07) Drains under bike path to BC. Invert buried, outlet forming gully. 2180, 2181 Drains at top of bike path to rocked gully. Invert 1/3 full of deposits. 2182, 2183, Moderate no Drains I-70 under bike path to midway down fill slope. ully starting to form Poor yes Corrugated metal pipe is clogged with sediments. Located just downstream spillway. Some erosion at outlet ood yes yes Drains WB uncontrolled cut slope. Shoulder is not paved. Deposits at invert are 0.5' deep. 2081,2082, 2083, 2150(07) * Mile Marker determined in the field using aerial photographs and existing CDOT markers (+/- 0.1 mile) * Inventory does not include all culverts on West Vail Pass * Inventory Lorch Thesis based from 1979 As-Built CDOT maps in efforts to uncover culverts Monitoring and Load Allocation A quantitative sediment yield was calculated for the various contributing erosional processes. Table 9 shows the sediment yield results. The information presented herein are the results of a quantitative analysis (Load Allocation and Sediment Budget, TMDL) which estimates the magnitude of sediments that are recommended to be exported from the basin every year. The recommend export load is intended to move the stream towards meeting TMDL stream health targets. With continued monitoring efforts (Sediment Source and Physical and Biological Stream Health Monitoring, TMDL) a better estimate of the sediments inputs and controls can be calculated; and the balance between the sediment load and biological and physical stream health can be better determined. Appendix C provides the spread sheet model used to calculate the sediment budget. 28

30 Table 9 Black ore Creek 2006 and 2007 Load Allocation and Sediment Budget* SOURCE CATEORY ZONES LA (Tons/Year) LA (Tons/Year) Applied Traction Sand Sand Stockpile Erosion Slope Mass Wasting Natural Background Black Lakes Channel Bed Active Storage Fill Slope ullies 1, Fill Slopes 1, Valley Floors Cut Slopes Accumulation Under Bridges Increased erosion of native slopes Bike path swales 1, Center Medians Increased Bank Erosion Other 0 0 Sediment Sources TOTAL LA BC Transport Capacity (TC) BC Assimilative Capacity (AC) 0 0 Exported Sediment Load 1,2, Recommended Exported Load (2006, 2007) 1,2, * The recommended exported load shall always be equal to, or greater than 6400 tons/year ** Load allocations are estimates based source monitoring data. See Appendix C for detail. ***Imported and exported load estimates reported by CDOT February,

31 Recommendations for Future Monitoring There are several reference points that need to be re-established during the 2008 monitoring efforts. Two TLPs, and were not present during the 2007 monitoring and need to be replaced. The right TLP at needs to be replaced due to hillslope slumping. The photographic monitoring station established at the USS gage station near should have a reference point established. Two CDOT bench marks located at and were not recovered; these photographic monitoring stations should have new reference points established. Additional photographic monitoring should be established near the and area. From 2004 to 2007 significant change occurred near these areas due to a breached beaver dam at and significant deposition at Photographs have been taken of these areas, however no TLP reference point has been set. Future monitoring may include a single depth measurement between the snow storage site and the native gully. Longitudinal and cross sections surveys, as well as pebble counts should continue at Monitoring of this site may provide information to better understand beaver activity and storage in Black ore Creek. This site may show three different transport scenarios; deposits depth behind beaver dams, transport of stored materials when breached, the aggradation rate once beaver dams are re-established. Fill slope gully forming at may include cross section surveys and photographic monitoring (photos 2033, 35, 36). Valley Floor delta deposit is now at an elevation high enough that runoff is routed to the north of the deposit down a swale at the toe of the fill slope. A monitoring post may be established at a different location to represent transport of materials into Black ore Creek. A breached beaver dam with lateral bar deposits at may be a good location for subsurface monitoring. A large culvert also forms a delta near The breached beaver dams at above USS gage 2190 may also be a good location to establish subsurface monitoring in the future. Monitoring results show that the fill slope slumping at is the cause of a failed culvert and may result to a gully. This site may be monitored in the future. A delta deposit is forming at the outlet of the culvert into Black ore Creek, photographs 2087, Exacerbated bank erosion locations and lengths have not been updated since Field notes showed exacerbated bank erosion at and 186.1, but these were not include in 2007 budget because no measurements were taken. Photograph 2086 is an example of large deposits that are not transported and changing the flow into the bank, resulting to exacerbated bank erosion. The Field uide needs to be updated with elevations that were re-established due to bent or disturbed TLPs; these include 186.8#3 lep, 186.8#1 lep, 187.1#1 lep, rep, ECB rep, and WTP #1 lep. 30

32 Abbreviations Black ore Creek (BC) Best Management Practice (BMP) Center Median (CM) Cut Slopes (CS) East Bound (EB) Erosion Control Basin (ECB) Fill Slopes (FS) ully () Large Woody Debris (LWD) Valley Floor (VF) Waste Water Treatment Plant (WTP) West Bound (WB) Attachments Appendix A: Raw data for Cross Section surveys Appendix B: Photographs Appendix C: Load Allocation Worksheet 31