Estimators |
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Below are estimators provided to assist with calculations frequently utilized during the development process. Some are self-explanatory, and others have instructions for use. In all cases, the estimators are based on the Gorham Land Use and Development Code. It is suggested that prior to the preparation of engineered plans you or your representative read the Land Use and Development Code to familiarize yourself with
requirements set forth in the Ordinance for development. |
Chapter 1, Section V - Definitions defines ‘Net Acreage’ and ‘Net Residential Density’. It is important that you realize the method for subtraction of land areas from the gross lot area differs from zone to zone. For example the Density Estimator for a Standard Subdivision for All Zones Other Than Rural provides a cell for the deduction of land area to be utilized for ‘streets and rights-of-way’. You must manually enter the gross lot area (GLA) of your parcel and area(s) to be deducted in the appropriate cells. This estimator will then calculate the total number of dwelling units allowed based on the Net Lot Area. The Density Estimator for a Standard Subdivision for the Rural Zone requires less data entry since the Land Use and Development Code requirement for the Rural zone is ‘15% of the gross lot area for roads and parking’. In this instance, the square footage is automatically calculated once the GLA of the parcel is entered into the appropriate cell. More detailed instructions are provided with the particular estimators.
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How to Use the Estimators:
Click here to go directly to Estimator
Click here to go directly to Estimator
Click here to go directly to Estimator
Density Estimator for a Standard Subdivision (Rural District only)
 This estimator will perform density calculations for a standard subdivision in accordance with Chapter 1 Section III of the Gorham Land Use and Development Code. Refer to the Gorham Land Use and Development Code for more specific information related to the Rural Zoning district, such as Space Standards, Permitted Uses, and Special Exceptions.
Step 1: After you have entered the project name (above), enter the Gross Lot Area for your parcel(s) in the cell to the right.
Step 2: In the Rural Zoning district, Ordinance requires the deduction of land area unsuitable for development, rights-of-way and parking areas, significant wetlands, steep slopes, etc. from the gross lot area. In all events, the shape of the parcel boundary and space standards such as lot width, depth and setbacks, topography, and location will ultimately affect the resultant number of lots, which may be less than the estimated number of dwelling units.
 Step 3: Based on the data entered in steps 1 and 2, the estimator will calculate the total number of dwelling units allowed, per Ordinance, by dividing the net lot area by the minimum lot area per dwelling unit. The results are for design purposes only. The final number of dwelling units may be less than the estimated number due to the required the type of structure, shape of the lot, topography, internal and adjacent streets, etc.The ‘Type of Structure’ portion of this estimator is interactive and is provided so that, during the design stage, a variety of combinations can quickly be considered. Once you know the maximum number of dwelling units allowed, you can determine the number of single-family, duplex, tri-plex and multi-family dwelling structures.
In the Rural Zoning district, individual lots may vary in size as long as the subdivision conforms to the overall net residential density of the parcel, and no lot for a single family dwelling unit is smaller than 40,000 square feet in area. See the Gorham Land Use Ordinance - Rural District for all related requirements.
Cost Estimating Form
 This interactive spread sheet is provided to assist in the preparation of an itemized cost estimate for work that is to be secured by Performance Guarantee. The Cost Estimating Form must include all approved public and quasi-public improvements including, but not limited to, road construction, fire ponds, the installation of public sewer and public water, roadway monumentation, and the installation of street trees, required landscaping, etc.
Estimator for Water Supply Costs
 Chapter II Section IX of the Gorham Land Use and Development Code requires that certain projects conduct an analysis to determine if the development
needs to be serviced by public water. This paper sets out the process to be used in conducting that analysis.Step 1. Determine the Site Layout to be Used in the Analysis
The Land Use and Development Code requires that the analysis of water supply be based on:
A. the proposed development scenario if the entire lot will be developed or subdivided and there is no potential for future development, or
B. a full build-out scenario if the Planning Board requires it or if only a portion of the site is proposed to be developed.
The full build-out scenario is be based on the development of the site and is based on the allowed zoning density with public water taking into account site constraints and Town regulations. Planning Board approval is required.
Therefore, the applicant should meet with the Town Planner prior to conducting the analysis to review the proposed development scenario to be used. If the density of the proposed development scenario is significantly less than that allowed by zoning, or if only a portion of the site is proposed to be developed, or if there will be potential for additional future development, the Town Planner will require that the applicant prepare a full build-out scenario to be used in the analysis. The Planner shall refer this scenario to the Planning Board for its approval. The Planning Board shall approve the scenario for the purpose of the water supply analysis if it finds that it represents a reasonable use of the land considering site conditions, the interest of the owner/applicant, and the Town’s regulations and will not
bias the water supply analysis.
The approved development scenario should be shown on a sketch plan that is submitted with the worksheet (see Step 3).
Step 2. Determine the Public Water System Needed to Supply the Proposed Layout
Once the development scenario to be used in the analysis has been approved by the Town Planner and Planning Board, the applicant shall determine the public water supply system needed to service the development scenario. This shall be done in conjunction with the Portland Water District. The District shall provide written documentation that it believes the proposed system is rationale to serve the development scenario.
The proposed public water supply system should be shown on the sketch plan of the development scenario submitted with the worksheet (see Step 3) together with any supporting documentation.
Step 3. Complete the following Cost Estimator Worksheet
The final step in the analysis is to complete the worksheet comparing the Public Water Cost Per Unit with the Maximum Private Water Cost Per Unit in accordance with the formula set out in the Land Use and Development Code. The worksheet is set up as an Excel spreadsheet. If the appropriate variables are entered in the spreadsheet, it calculates both the public and private water supply costs.
Here are instructions for completing the worksheet:
 The required information should be provided in the yellow boxes on the spreadsheet.1. Enter the number of dwelling units in the project. This should include any existing units that are part of the project that are not served by public water.
2. Enter the number of lineal feet of water main that will need to be constructed in an existing street or road to serve the development. This should include only construction where existing pavement will need to be disturbed and replaced.
3. Enter the number of lineal feet of water main that will need to be constructed in new streets or in rights-of-way that are outside of streets or roads. This should include all construction that will not involve disturbing existing pavement.
4. This is a supplied cost – do not enter anything in this box.
5. Enter the name of the project.
6. Enter the name of the owner or applicant.
7. Enter the zoning district in which the project is located. If it is located in more than one zone, enter all of the zones and attach a sketch showing what parts of the property are in which zones if that is not shown on the development scenario.
8. Enter the date of submission of the analysis.
9. Enter the month and year of the analysis.
11. This is a supplied figure – do not enter anything in this box.
12. The worksheet will calculate the inflation factor based upon the information supplied – do not enter anything in this box.
13. If the project will involve ledge trench due to shallow bedrock conditions, enter the estimated number of lineal feet of ledge trench. Attach the rational for your estimate to the printed worksheet when you submit it.
14a. The worksheet will calculate the estimated ledge cost based upon the data provided – do not enter anything in this box.
14b. You may also provide an alternate estimate of the cost of ledge removal to install the public water system. This is an option – you do not have to complete this box. If you prepare an alternate cost, enter the total ledge removal cost estimate in this box and attach the basis for the estimate to the printed worksheet you submit.
15. The worksheet will select the greater of 14a or 14b to be used in the analysis and show it in this box – do not enter anything in this box.
16. If the project will involve any extraordinary costs such as special provisions for crossing a stream or for pressure reduction or augmentation, enter the estimated cost for these provisions. Any special costs shall be included only if the Portland Water District verifies that the provisions are needed to serve the development scenario.
17-26. Based upon the information provided, the worksheet will calculate the balance of the data and display it in the appropriate boxes. Box 25 shows the Public Water Cost per Unit. Box 26 shows the Maximum Private Water Cost per Unit. If the public water cost per unit is less than the maximum private cost per unit, the Planning Board will require that public water be used to service the development.
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