Standard Water Quality Report
Download Raw Water Quality Data CSVSample Point - 89OPCRaw |
Download Sample Point Report CSV / Inflow: Yes / Outflow: No
Date | Method of Flow | Flow - Field (gal/min) | pH - Field (S.U.) | pH - Lab (S.U.) | ORP - Field (mvolts) | DO - Field (mg/L) | Temp - Field (C) | Cond - Lab (umhos/cm) | Alkalinity - Field (mg/L) | Alkalinity - Lab (mg/L) | Acidity - Lab (mg/L) | T. Fe - Lab (mg/L) | D. Fe - Lab (mg/L) | T. Mn - Lab (mg/L) | D. Mn - Lab (mg/L) | T. Al - Lab (mg/L) | D. Al - Lab (mg/L) | SO4 - Lab (mg/L) | TSS - Lab (mg/L) | Ferrous Iron (mg/L) Lab |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2020-06-15 | Assumed | 80 | 3.32 | 3.28 | 430 | 7.87 | 21.1 | 930 | 0 | 0 | 120.96 | 15.75 | -- | -- | -- | 7.33 | -- | 450.3 | 13 | -- |
| 2024-05-07 | Estimated | 300 | 3.05 | 3.42 | 424 | -- | 12.9 | 776 | 0 | <0.10 | 214.92 | 3.15 | -- | 2.17 | -- | 10.78 | -- | 374.6 | <5 | -- |
| 2025-05-07 | Assumed | 110 | 3.39 | 3.69 | -- | 6.45 | 14.2 | 763 | 0 | < 10 | 77 | 13 | -- | 1.89 | -- | 10 | -- | 309 | 19 | -- |
| Minimum: | 0 | 80 | 3.05 | 3.28 | 424 | 6.45 | 12.9 | 763 | 0 | 0 | 77 | 3.15 | -- | 1.89 | -- | 7.33 | -- | 309 | 13 | -- |
| Maximum: | 0 | 300 | 3.39 | 3.69 | 430 | 7.87 | 21.1 | 930 | 0 | 0 | 214.92 | 15.75 | -- | 2.17 | -- | 10.78 | -- | 450.3 | 19 | -- |
| Average: | 0 | 163 | 3.25 | 3.46 | 427 | 7.16 | 16.1 | 823 | 0 | 0 | 137.6 | 10.63 | -- | 2.03 | -- | 9.37 | -- | 378.0 | 16.0 | -- |
| Range: | 0 | 220 | 0.34 | 0.41 | 6 | 1.42 | 8.2 | 167 | 0 | 0 | 137.92 | 12.6 | -- | 0.28 | -- | 3.45 | -- | 141.3 | 6 | -- |
| Median: | 0 | 110 | 3.32 | 3.42 | 427 | 7.16 | 14.2 | 776 | 0 | 0 | 120.96 | 13 | -- | 2.03 | -- | 10 | -- | 374.6 | 16 | -- |
| Loading (lb/day): | -- | -- | 331.04 | 14.56 | -- | 5.16 | -- | 19.71 | -- |
Sample Point Description:
Somewhat arbitrary sample point location within the OPC that is used as one of the "raw untreated" AMD sources after various seeps are collected. Sample just upstream of the Pipe 1 & Pipe 2 discharges.
- Records with no value are not included in statistical calculations.
- Values lower than the minimum detection limit are assumed to be 0.
- Average pH is calculated using the arithmetic mean of pH values. Hydronium ion concentrations were not used.
- This work is licensed under the Creative Commons Attribution-NonCommercial-ShareAlike License.
To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-sa/2.5/ or send a letter to Creative Commons, 559 Nathan Abbott Way, Stanford, California 94305, USA.
Sample Point - Culvert |
Download Sample Point Report CSV / Inflow: Yes / Outflow: No
Date | Method of Flow | Flow - Field (gal/min) | pH - Field (S.U.) | pH - Lab (S.U.) | ORP - Field (mvolts) | DO - Field (mg/L) | Temp - Field (C) | Cond - Lab (umhos/cm) | Alkalinity - Field (mg/L) | Alkalinity - Lab (mg/L) | Acidity - Lab (mg/L) | T. Fe - Lab (mg/L) | D. Fe - Lab (mg/L) | T. Mn - Lab (mg/L) | D. Mn - Lab (mg/L) | T. Al - Lab (mg/L) | D. Al - Lab (mg/L) | SO4 - Lab (mg/L) | TSS - Lab (mg/L) | Ferrous Iron (mg/L) Lab |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2024-05-07 | Measured | 13 | 4.34 | 3.99 | 417 | -- | 15.3 | 732 | 0 | <0.10 | 102.08 | 0.68 | -- | 2.86 | -- | 10.43 | -- | 491.3 | <5 | -- |
| 2025-05-07 | Measured | 3 | 6.5 | -- | -- | 8.79 | 15.6 | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Minimum: | 0 | 3 | 4.34 | 3.99 | 417 | 8.79 | 15.3 | 732 | 0 | -- | 102.08 | 0.68 | -- | 2.86 | -- | 10.43 | -- | 491.3 | -- | -- |
| Maximum: | 0 | 13 | 6.5 | 3.99 | 417 | 8.79 | 15.6 | 732 | 0 | -- | 102.08 | 0.68 | -- | 2.86 | -- | 10.43 | -- | 491.3 | -- | -- |
| Average: | 0 | 8 | 5.42 | 3.99 | 417 | 8.79 | 15.5 | 732 | 0 | -- | 102.1 | 0.68 | -- | 2.86 | -- | 10.43 | -- | 491.3 | -- | -- |
| Range: | 0 | 10 | 2.16 | 0 | 0 | 0 | 0.3 | 0 | 0 | -- | 0 | 0 | -- | 0 | -- | 0 | -- | 0 | -- | -- |
| Median: | 0 | 8 | 5.42 | 3.99 | 417 | 8.79 | 15.45 | 732 | 0 | -- | 102.08 | 0.68 | -- | 2.86 | -- | 10.43 | -- | 491.3 | -- | -- |
| Loading (lb/day): | -- | -- | 15.95 | 0.11 | -- | 0.45 | -- | 1.63 | -- |
Sample Point Description:
Culvert at the beginning/start of the OPC. Only sampled when there's flow coming out of it.
- Records with no value are not included in statistical calculations.
- Values lower than the minimum detection limit are assumed to be 0.
- Average pH is calculated using the arithmetic mean of pH values. Hydronium ion concentrations were not used.
- This work is licensed under the Creative Commons Attribution-NonCommercial-ShareAlike License.
To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-sa/2.5/ or send a letter to Creative Commons, 559 Nathan Abbott Way, Stanford, California 94305, USA.
Sample Point - APipe1 |
Download Sample Point Report CSV / Inflow: Yes / Outflow: No
Date | Method of Flow | Flow - Field (gal/min) | pH - Field (S.U.) | pH - Lab (S.U.) | ORP - Field (mvolts) | DO - Field (mg/L) | Temp - Field (C) | Cond - Lab (umhos/cm) | Alkalinity - Field (mg/L) | Alkalinity - Lab (mg/L) | Acidity - Lab (mg/L) | T. Fe - Lab (mg/L) | D. Fe - Lab (mg/L) | T. Mn - Lab (mg/L) | D. Mn - Lab (mg/L) | T. Al - Lab (mg/L) | D. Al - Lab (mg/L) | SO4 - Lab (mg/L) | TSS - Lab (mg/L) | Ferrous Iron (mg/L) Lab |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2020-06-15 | Bucket | 2 | 3.61 | 3.45 | 375 | 5.53 | 13.7 | 1759 | 0 | 0 | 450.34 | 83.58 | -- | -- | -- | 26.66 | -- | 1131.9 | 11 | -- |
| 2025-05-07 | Estimated | 5 | 3.14 | 3.28 | -- | 3.74 | 11.9 | 762 | 0 | < 10 | 92 | 1.85 | -- | 1.23 | -- | 9.2 | -- | 290 | < 5 | -- |
| Minimum: | 0 | 2 | 3.14 | 3.28 | 375 | 3.74 | 11.9 | 762 | 0 | 0 | 92 | 1.85 | -- | 1.23 | -- | 9.2 | -- | 290 | 11 | -- |
| Maximum: | 0 | 5 | 3.61 | 3.45 | 375 | 5.53 | 13.7 | 1759 | 0 | 0 | 450.34 | 83.58 | -- | 1.23 | -- | 26.66 | -- | 1131.9 | 11 | -- |
| Average: | 0 | 4 | 3.38 | 3.37 | 375 | 4.64 | 12.8 | 1,261 | 0 | 0 | 271.2 | 42.72 | -- | 1.23 | -- | 17.93 | -- | 711.0 | 11.0 | -- |
| Range: | 0 | 3 | 0.47 | 0.17 | 0 | 1.79 | 1.8 | 997 | 0 | 0 | 358.34 | 81.73 | -- | 0 | -- | 17.46 | -- | 841.9 | 0 | -- |
| Median: | 0 | 3.5 | 3.38 | 3.37 | 375 | 4.64 | 12.8 | 1260.5 | 0 | 0 | 271.17 | 42.72 | -- | 1.23 | -- | 17.93 | -- | 710.95 | 11 | -- |
| Loading (lb/day): | -- | -- | 8.18 | 1.06 | -- | 0.07 | -- | 0.6 | -- |
Sample Point Description:
AMD; One of the many AMD seep sources that are influent to the SR89 system
- Records with no value are not included in statistical calculations.
- Values lower than the minimum detection limit are assumed to be 0.
- Average pH is calculated using the arithmetic mean of pH values. Hydronium ion concentrations were not used.
- This work is licensed under the Creative Commons Attribution-NonCommercial-ShareAlike License.
To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-sa/2.5/ or send a letter to Creative Commons, 559 Nathan Abbott Way, Stanford, California 94305, USA.
Sample Point - APipe2 |
Download Sample Point Report CSV / Inflow: Yes / Outflow: No
Date | Method of Flow | Flow - Field (gal/min) | pH - Field (S.U.) | pH - Lab (S.U.) | ORP - Field (mvolts) | DO - Field (mg/L) | Temp - Field (C) | Cond - Lab (umhos/cm) | Alkalinity - Field (mg/L) | Alkalinity - Lab (mg/L) | Acidity - Lab (mg/L) | T. Fe - Lab (mg/L) | D. Fe - Lab (mg/L) | T. Mn - Lab (mg/L) | D. Mn - Lab (mg/L) | T. Al - Lab (mg/L) | D. Al - Lab (mg/L) | SO4 - Lab (mg/L) | TSS - Lab (mg/L) | Ferrous Iron (mg/L) Lab |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2020-06-15 | Bucket | 20 | 3.36 | 3.43 | 434 | 2.19 | 11.2 | 638 | 0 | 0 | 77.62 | 7 | -- | -- | -- | 4.28 | -- | 271.6 | 6 | -- |
| Minimum: | 0 | 20 | 3.36 | 3.43 | 434 | 2.19 | 11.2 | 638 | 0 | 0 | 77.62 | 7 | -- | -- | -- | 4.28 | -- | 271.6 | 6 | -- |
| Maximum: | 0 | 20 | 3.36 | 3.43 | 434 | 2.19 | 11.2 | 638 | 0 | 0 | 77.62 | 7 | -- | -- | -- | 4.28 | -- | 271.6 | 6 | -- |
| Average: | 0 | 20 | 3.36 | 3.43 | 434 | 2.19 | 11.2 | 638 | 0 | 0 | 77.6 | 7.00 | -- | -- | -- | 4.28 | -- | 271.6 | 6.0 | -- |
| Range: | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | -- | -- | -- | 0 | -- | 0 | 0 | -- |
| Median: | 0 | 20 | 3.36 | 3.43 | 434 | 2.19 | 11.2 | 638 | 0 | 0 | 77.62 | 7 | -- | -- | -- | 4.28 | -- | 271.6 | 6 | -- |
| Loading (lb/day): | -- | -- | 18.66 | 1.68 | -- | -- | -- | 1.03 | -- |
Sample Point Description:
AMD; seep discharges through pipe. I think this is the longer more southern pipe that discharges into OPC
- Records with no value are not included in statistical calculations.
- Values lower than the minimum detection limit are assumed to be 0.
- Average pH is calculated using the arithmetic mean of pH values. Hydronium ion concentrations were not used.
- This work is licensed under the Creative Commons Attribution-NonCommercial-ShareAlike License.
To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-sa/2.5/ or send a letter to Creative Commons, 559 Nathan Abbott Way, Stanford, California 94305, USA.
Sample Point - 89OPC |
Download Sample Point Report CSV / Inflow: No / Outflow: No
Date | Method of Flow | Flow - Field (gal/min) | pH - Field (S.U.) | pH - Lab (S.U.) | ORP - Field (mvolts) | DO - Field (mg/L) | Temp - Field (C) | Cond - Lab (umhos/cm) | Alkalinity - Field (mg/L) | Alkalinity - Lab (mg/L) | Acidity - Lab (mg/L) | T. Fe - Lab (mg/L) | D. Fe - Lab (mg/L) | T. Mn - Lab (mg/L) | D. Mn - Lab (mg/L) | T. Al - Lab (mg/L) | D. Al - Lab (mg/L) | SO4 - Lab (mg/L) | TSS - Lab (mg/L) | Ferrous Iron (mg/L) Lab |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2020-06-15 | Assumed | 100 | 3.3 | 3.3 | 480 | 8.12 | 29 | 921 | 0 | 0 | 84.91 | 4.39 | -- | -- | -- | 5.12 | -- | 386.3 | 8 | -- |
| 2024-05-07 | Estimated | 330 | 2.96 | 3.34 | 483 | -- | 22.3 | 908 | 0 | <0.10 | 131.53 | 1.21 | -- | 2.83 | -- | 8.93 | -- | 451.0 | <5 | -- |
| 2025-05-07 | Assumed | 115 | 3.25 | 3.33 | -- | 10.6 | 20.8 | 835 | 0 | < 10 | 77 | 1.51 | -- | 1.83 | -- | 7.1 | -- | 162 | < 5 | -- |
| Minimum: | 0 | 100 | 2.96 | 3.3 | 480 | 8.12 | 20.8 | 835 | 0 | 0 | 77 | 1.21 | -- | 1.83 | -- | 5.12 | -- | 162 | 8 | -- |
| Maximum: | 0 | 330 | 3.3 | 3.34 | 483 | 10.6 | 29 | 921 | 0 | 0 | 131.53 | 4.39 | -- | 2.83 | -- | 8.93 | -- | 451.0 | 8 | -- |
| Average: | 0 | 182 | 3.17 | 3.32 | 482 | 9.36 | 24.0 | 888 | 0 | 0 | 97.8 | 2.37 | -- | 2.33 | -- | 7.05 | -- | 333.1 | 8.0 | -- |
| Range: | 0 | 230 | 0.34 | 0.04 | 3 | 2.48 | 8.2 | 86 | 0 | 0 | 54.53 | 3.18 | -- | 1 | -- | 3.81 | -- | 289 | 0 | -- |
| Median: | 0 | 115 | 3.25 | 3.33 | 481.5 | 9.36 | 22.3 | 908 | 0 | 0 | 84.91 | 1.51 | -- | 2.33 | -- | 7.1 | -- | 386.3 | 8 | -- |
| Loading (lb/day): | -- | -- | 243.41 | 4.05 | -- | 6.88 | -- | 17.13 | -- |
Sample Point Description:
Effluent of the SR89 OPC; Sampled at the end of the OPC before entering the VFP
- Records with no value are not included in statistical calculations.
- Values lower than the minimum detection limit are assumed to be 0.
- Average pH is calculated using the arithmetic mean of pH values. Hydronium ion concentrations were not used.
- This work is licensed under the Creative Commons Attribution-NonCommercial-ShareAlike License.
To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-sa/2.5/ or send a letter to Creative Commons, 559 Nathan Abbott Way, Stanford, California 94305, USA.
Sample Point - 89VFP |
Download Sample Point Report CSV / Inflow: No / Outflow: No
Date | Method of Flow | Flow - Field (gal/min) | pH - Field (S.U.) | pH - Lab (S.U.) | ORP - Field (mvolts) | DO - Field (mg/L) | Temp - Field (C) | Cond - Lab (umhos/cm) | Alkalinity - Field (mg/L) | Alkalinity - Lab (mg/L) | Acidity - Lab (mg/L) | T. Fe - Lab (mg/L) | D. Fe - Lab (mg/L) | T. Mn - Lab (mg/L) | D. Mn - Lab (mg/L) | T. Al - Lab (mg/L) | D. Al - Lab (mg/L) | SO4 - Lab (mg/L) | TSS - Lab (mg/L) | Ferrous Iron (mg/L) Lab |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2020-06-15 | Bucket | 103 | -- | 6.79 | -- | -- | -- | 958 | -- | 184.1 | -152.87 | 11.82 | 4.43 | -- | -- | 0.4 | -- | 362.1 | 42 | -- |
| 2024-05-07 | Measured | 330 | 6.23 | 6.74 | 172 | -- | 16.3 | 966 | 147 | 172.00 | -151.24 | 18.47 | -- | 2.32 | -- | 1.01 | -- | 473.1 | 37 | -- |
| 2025-05-07 | Bucket, Composite | 115 | 6.58 | 6.96 | -- | 3.19 | 16.2 | 869 | 140 | 73 | -59 | 25.6 | -- | 2.18 | -- | 1.6 | -- | 175 | 49 | -- |
| Minimum: | 0 | 103 | 6.23 | 6.74 | 172 | 3.19 | 16.2 | 869 | 140 | 73 | -152.87 | 11.82 | 4.43 | 2.18 | -- | 0.4 | -- | 175 | 37 | -- |
| Maximum: | 0 | 330 | 6.58 | 6.96 | 172 | 3.19 | 16.3 | 966 | 147 | 184.1 | -59 | 25.6 | 4.43 | 2.32 | -- | 1.6 | -- | 473.1 | 49 | -- |
| Average: | 0 | 183 | 6.41 | 6.83 | 172 | 3.19 | 16.3 | 931 | 143.50 | 143 | -121.0 | 18.63 | 4.43 | 2.25 | -- | 1.00 | -- | 336.7 | 42.7 | -- |
| Range: | 0 | 227 | 0.35 | 0.22 | 0 | 0 | 0.1 | 97 | 7 | 111.1 | 93.87 | 13.78 | 0 | 0.14 | -- | 1.2 | -- | 298.1 | 12 | -- |
| Median: | 0 | 115 | 6.41 | 6.79 | 172 | 3.19 | 16.25 | 958 | 143.5 | 172 | -151.24 | 18.47 | 4.43 | 2.25 | -- | 1.01 | -- | 362.1 | 42 | -- |
| Loading (lb/day): | 388.31 | 337.03 | -290.24 | 41.09 | 5.48 | 6.11 | -- | 2.24 | -- |
Sample Point Description:
Effluent of the SR89 VFP
- Records with no value are not included in statistical calculations.
- Values lower than the minimum detection limit are assumed to be 0.
- Average pH is calculated using the arithmetic mean of pH values. Hydronium ion concentrations were not used.
- This work is licensed under the Creative Commons Attribution-NonCommercial-ShareAlike License.
To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-sa/2.5/ or send a letter to Creative Commons, 559 Nathan Abbott Way, Stanford, California 94305, USA.
Sample Point - 89SPWL |
Download Sample Point Report CSV / Inflow: No / Outflow: Yes
Date | Method of Flow | Flow - Field (gal/min) | pH - Field (S.U.) | pH - Lab (S.U.) | ORP - Field (mvolts) | DO - Field (mg/L) | Temp - Field (C) | Cond - Lab (umhos/cm) | Alkalinity - Field (mg/L) | Alkalinity - Lab (mg/L) | Acidity - Lab (mg/L) | T. Fe - Lab (mg/L) | D. Fe - Lab (mg/L) | T. Mn - Lab (mg/L) | D. Mn - Lab (mg/L) | T. Al - Lab (mg/L) | D. Al - Lab (mg/L) | SO4 - Lab (mg/L) | TSS - Lab (mg/L) | Ferrous Iron (mg/L) Lab |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2020-06-15 | Assumed | 105 | 6.78 | 6.66 | 170 | 10.12 | 28.4 | 922 | 97 | 82.45 | -70.72 | 3.45 | -- | -- | -- | 0.13 | -- | 415.2 | 29 | -- |
| 2024-05-07 | Estimated | 330 | 4.36 | 4.42 | 433 | -- | 21.9 | 951 | 0 | <0.10 | 29.65 | 1.77 | 0.41 | 2.46 | 2.45 | 1.25 | 1.11 | 576.6 | 16 | -- |
| 2025-05-07 | Estimated | 150 | 4.05 | 4.09 | -- | 10.17 | 17.9 | 875 | 0 | < 10 | 22 | 0.83 | -- | 1.95 | -- | 1.6 | -- | 424 | < 5 | -- |
| Minimum: | 0 | 105 | 4.05 | 4.09 | 170 | 10.12 | 17.9 | 875 | 0 | 82.45 | -70.72 | 0.83 | 0.41 | 1.95 | 2.45 | 0.13 | 1.11 | 415.2 | 16 | -- |
| Maximum: | 0 | 330 | 6.78 | 6.66 | 433 | 10.17 | 28.4 | 951 | 97 | 82.45 | 29.65 | 3.45 | 0.41 | 2.46 | 2.45 | 1.6 | 1.11 | 576.6 | 29 | -- |
| Average: | 0 | 195 | 5.06 | 5.06 | 302 | 10.15 | 22.7 | 916 | 32.33 | 82 | -6.4 | 2.02 | 0.41 | 2.21 | 2.45 | 0.99 | 1.11 | 471.9 | 22.5 | -- |
| Range: | 0 | 225 | 2.73 | 2.57 | 263 | 0.050000000000001 | 10.5 | 76 | 97 | 0 | 100.37 | 2.62 | 0 | 0.51 | 0 | 1.47 | 0 | 161.4 | 13 | -- |
| Median: | 0 | 150 | 4.36 | 4.42 | 301.5 | 10.15 | 21.9 | 922 | 0 | 82.45 | 22 | 1.77 | 0.41 | 2.21 | 2.45 | 1.25 | 1.11 | 424 | 22.5 | -- |
| Loading (lb/day): | 122.42 | 104.06 | 22.67 | 4.29 | 1.63 | 6.64 | 9.72 | 2.67 | 4.4 |
Sample Point Description:
Effluent of the SR89 Settling Pond/Wetland; Not a very well defined sampling point location
- Records with no value are not included in statistical calculations.
- Values lower than the minimum detection limit are assumed to be 0.
- Average pH is calculated using the arithmetic mean of pH values. Hydronium ion concentrations were not used.
- This work is licensed under the Creative Commons Attribution-NonCommercial-ShareAlike License.
To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-sa/2.5/ or send a letter to Creative Commons, 559 Nathan Abbott Way, Stanford, California 94305, USA.
Sample Point - SR89 |
Download Sample Point Report CSV / Inflow: No / Outflow: No
Sample Point Description:
AMD; SR89 discharge; Currently, this data is pre-construction from 1995- 2017 with most data being collected prior to 2002.
- Records with no value are not included in statistical calculations.
- Values lower than the minimum detection limit are assumed to be 0.
- Average pH is calculated using the arithmetic mean of pH values. Hydronium ion concentrations were not used.
- This work is licensed under the Creative Commons Attribution-NonCommercial-ShareAlike License.
To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-sa/2.5/ or send a letter to Creative Commons, 559 Nathan Abbott Way, Stanford, California 94305, USA.