Ill. Admin. Code tit. 35, § 671.APPENDIX A
For unconfined unconsolidated, or unconfined non-fractured bedrock aquifers the lateral radius of influence can be calculated as follows:
| r | = | the square root of | Qt |
| 4524nH |
Where
| r | = | radius of influence (feet) |
| Q | = | daily flow from the well under normal operational conditions (cubic feet per day) |
| t | = | time that the well is pumped under normal operational conditions (minutes) |
| H | = | open interval or length of well screen (feet) |
| n | = | aquifer porosity (see Figure A-1) unless more site specific information is available |
| Sand | 0.21 | Sandstone | 0.06 |
| Gravel | 0.19 | Limestones: | |
| Sand & Gravel | 0.15 | Primary dolomites | 0.18 |
| Secondary dolomites | 0.18 | ||
| Figure A-1 |