SPR: Soil Potential Ratings PENILAIAN POTENSI TANAH

1. SPR: Soil Potential Ratings PENILAIAN POTENSI TANAH

2. SPR: Soil Potential Ratings Konsep SPR diperkenalkanoleh Beatty, Petersen & Swindale (1979). The National Soils Handbook §603.09 (U.S. Department of Agriculture, 1983b) explains the system and procedures in detail. Metodeinidapatdigunakanuntukmelengkapiinterpretasihasilsurveitanahdenganpendekatan yang lebihberbasisekonomis. Beatty, M.T., Petersen, G.W. & Swindale, L.D. (ed). 1979. Planning the uses and management of land. Agronomy Monograph 21, Madison: American Society of Agronomy. xxvii,1028 pp. HD 111 B36 1979 Mann U.S. Department of Agriculture, S.C.S. 1983b. National soils handbook. Title 430, Washington, DC: US Government Printing Office.

3. SPR: Soil Potential Ratings Definisi SPR adalahkelas-kelasygmenyatakankualitasrelatifsuatutanahuntukpenggunaantertentudibandingkandnegantanah-tanahlainnyadisuatulokasi yang dievaluasi. Tigahalberikutinidipertimbangkandalampenilaian(rating): Hasilatautingkatkeragaan (performance), Biayarelatifpenerapanteknologi modern untukmeminimumkanefekakibatygditimbulkanolehfaktorpembatastanah, dan Efekburukakibatpembatasygkontinyuspadanilai-nilaisosial, ekonomidanlingkungan. Sumber:

4. SPR: Soil Potential Ratings TUJUAN Pendekatanyglebih modern dibandingIndeksStorieuntukmengkuantifikasikan “kesesuaianlahan” relatif dg caraindeksparametrik. Penilaianinidigunakanuntuktujuanperencanaan, bukanuntukrekomendasipenggunaanlahan. Pendekataninimengukurkesesuaian-relatifuntuksuatupenggunaan-lahan. Metodeinidapatmembantuparaperencanamemprioritaskanlahan-lahanygharusdipertahankansebagaipertanian. They also identify the general source of the problem. They are especially intended to replace limitations tables, which are based on physical factors without explicit economic interpretation. Tujuanutama SPR, sebagaipenggantitabelfaktorpembatas (mis., interpretasihasilsurveitanah), adalahmemberikanperkiraannilaiekonomisuntuksetiap “pembatas”.

5. SPR: Soil Potential Ratings Klasifikasi Criteria are established locally for the area in which the ratings are to be made. The following classes are recognized: Very high potential. Production or performance is at or above local standards because soil conditions are exceptionally favorable, installation or management costs are low, and there are no soil limitations. High potential. Production or performance is at or above local standards; costs of measures for overcoming soil limitations are judged locally to be favorable in relation to the expected performance, and soil limitations continuing after corrective measures are installed do not detract appreciably from environmental quality or economic returns. Sumber:

6. SPR: Soil Potential Ratings Classification Criteria are established locally for the area in which the ratings are to be made. The following classes are recognized: 3. Medium potential. Production or performance is somewhat below local standards; or costs of measures for overcoming soil limitations are high, or soil limitations continuing after corrective measures are installed detract somewhat from environmental quality or economic returns. 4. Low potential. Production or performance is significantly below local standards; or costs of measures for overcoming soil limitations are very costly, or soil limitations continuing after corrective measures are installed detract appreciably from environmental quality or economic returns. 5. Very low potential. Production or performance is much below local standards; or there are severe soil limitations for which economically feasible measures are unavailable, or soil limitations continuing after corrective measures are installed seriously detract from environmental quality or economic returns. Notice the use of or conditions. The concept of economic feasibility is explicit in this system. Sumber:

7. SPR: Soil Potential Ratings General concept of the Soil Potential Index The ratings are classes based on the index, which is a numerical rating of relative suitability. General form: SPI = P - (CM + CL) Where: SPI = Soil Potential Index; P = index of yield or other measure of performance, as locally established; CM = index of costs of corrective measures to overcome or minimize the effects of soil limitations; CL = index of costs resulting from continuing limitations Notes: This is not a detailed economic analysis; relative ratings are all that are needed; however, the three indices must be on commensurate scales. CM and CL must be measured on the same time scale (usually, annual, with present value of future costs used to bring CL to the same scale as CM). P is a percentage of a locally-established reference yield or performance. It may be >100%. Key point: the soil productivity is balanced against the costs for corrective measures and continuing limitations. Corrective measures can be one-time, such as land improvements, or continuing, such as fertilization. Sumber:

8. SPR: Soil Potential Ratings The P factor “P is an index of performance or yield standard for the area. It is established and defined locally.” P=100 for a reference soil, usually the best or one of the best soils for the use. Then the expected performance yield for each soil is compared to the standard, and P is established as the percent of standard. P is not an actual yield measurement. For some bizarre reason, higher yields are reflected in P, but lower yields are reflected in CL. This makes no sense. Example: if reference yield = 120, then if this soil’s yield is 132, P = (132/120)* 100 = 110. If reference yield is 100, then this soil’s P = (132/100)*100 = 132. For non-productive uses (e.g., engineering uses), P = 100 and costs in CM and CL must be normalized to this.

9. SPR: Soil Potential Ratings FAKTOR CM “CM is an index of added costs above a defined standard installation or management system that is commonly used if there are no soil limitations that must be overcome.” At this level, CM = 0. It is possible that CM<0 if even the ‘standard’ installation is not needed in an exceptional case. Examples of installations are drainage systems, or construction of an engineering work such as a septic system. For each type of added cost, a point value is assigned (by a local committee) to each level of costs. These are calibrated such that 1 point of CM is equivalent to 1 point of P. This is relatively easy to establish for productive uses such as crops: if P = 100 represents a gross margin of $500 ha-1, then 1 point of CM should represent $5 ha-1.

10. SPR: Soil Potential Ratings Example: Corrective measures and their costs for dwellings without basements (from (U.S. Department of Agriculture, 1983b): From this table we can infer that 1 point of CM = $100, so that if P = 100, the value of a dwelling without basement is $10,000 after the ‘normal’ costs of construction are taken into account. An important part of determining CM is the identification of workable technologies and their costs; in the preceding example, which limitations can be corrected (note that no excavation was allowed on slopes over 30%) and their costs.

11. SPR: Soil Potential Ratings The CL factor CM is an indx of limitations that continue after corrective measures (taken into account in CM) have been applied. These are of three types: Continuing performance, such as low yield, inconvenience, discomfort, probability of periodic failure (especially of engineering works). This type of continuing limitation should be included in P, not in CL!; Periodic maintenance costs to maintain performance, e.g., renewal of a septic systems or periodic maintenance of a drainage system; Off-site damages from the use, such as sedimentation or pollution. The easiest to establish are performance limitations for crops; this is just a ratio of yield reduction to standard yield, i.e., percent reduction in yield. For example, if the standard yield is 120, and a map unit is expected to yield 90 even after all corrective measures have been applied, CL = (120-90/120)*100 = 25. This will be subtracted from P (why didn’t they just compute it in P to begin with?). For other expenses, the cost is normalized to P = 100 and usually expressed in present value.

12. SPR: Soil Potential Ratings Example rating table From (U.S. Department of Agriculture, 1983b): SPR = P - (CM + CL) = 100 - (6 + 7) =87.

13. SPR: Soil Potential Ratings SubjektivitasdalamSistem SPR Semuabagiandarisisteminiditurunkansecaralokal, biasanyadenganjalankonsultasiberbagaipihakpenggunalahandanagen-agen-nya. Thus the actual ratings can be arbitrarily adjusted, however, the soil rankings are less arbitrary, although these can be influenced by the weight given to corrective measures vs. the performance index.

14. SPR: Soil Potential Ratings HubungandenganMetodeEvaluasiLahan FAO The ‘Land Utilization Type’ is a single, high-technology type, where all possible corrective measures have been applied; Sistem SPR meng-estimasiapakahinismeuaefektif-biayadanapakahadapembatasan yang kontinyu. Sumber:

15. SPR: Soil Potential Ratings Sumber:

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17. SPR: Soil Potential Ratings SPR adalahkelas-kelasygmneytaakankualitasrelatiufsuatutanahuntukpenggunaantertentudibandingkandnegantanah-tanah lain disuatulokasi (mis. Di Negara Bagian Connecticut -USA). KriteriapenilaiandikembangkanolehKomite Negara Bagiandneganmelibatkan stakeholder lokalygterkait. The soils information was provided by the USDA Natural Resources Conservation Service (NRCS). Then the performance and site conditions for a typical system were defined (Performance Standard). This provided a standard against which various combinations of soil properties for the soils within Connecticut could be compared.

18. SPR: Soil Potential Ratings StandarPerformans StandarPerformansterdiriatasduabagian. First, it identifies the capabilities of a typical SSDS. A typical system is assumed to be for a single family, 4-bedroom home on a 1-acre lot with a private well, or a ½-acre lot with public water supply. The system has a 1250 gallon septic tank and a 660 to 1000 square foot leaching field. Second, it addresses soil and landscape characteristics. This identifies the soil characteristics that are present in order for a typical system to be constructed. Karakteristik Tanah adalah: Slope kurangdari 15 %.. Lajuperkolasitanah 1 - 30 minutes per inch. Depth to seasonal high water table is greater than 36 inches below the soil surface. Kedalamanbatuaninduklebihdari 60 inches. Tanah tidakkebanjiran.

19. SPR: Soil Potential Ratings KELAS-KELAS RATING The rating class definitions refer to installing a SSDS that will meet state and local health code regulations. Soils with high potential have characteristics that meet the performance standard. A typical system can be installed at a cost of x. The cost of x represents the going rate for installing a SSDS. The actual value of x varies depending on many factors independent of soil properties. The cost of installing an leaching field is expressed as a multiple of x and is called the cost factor.** The cost factors of 3x and 3.5x mean that the estimated cost of a leaching field ranges from 3 to 3.5 times more than a field installed in a soil with high potential. These cost factors provide relative estimates of the costs in installing a SSDS. Soil potential ratings are listed in Tables 2 and 3.

20. SPR: Soil Potential Ratings SPR danfaktor-faktorbiayanya, denganasumsisuatusistem yang tipikal, didefinisikanberikut.

21. SPR: Soil Potential Ratings

22. SPR: Soil Potential Ratings Estimasipersenluasanlahandi Connecticut untuksetiapNilai (Rating) Potensial Tanah sbb: PotensialTinggi 15.3% Potensial Medium 12.4% Low Potential 30.7% Very Low Potential 7.2% Extremely Low Potential 13.7% Not Rated 20.7%

23. SPR: Soil Potential Ratings KRITERIA EVALUASI The evaluation criteria are soil properties that can significantly affect the cost of installing a SSDS. These soil properties correspond to criteria identified in the Connecticut State Health Code Regulations, as well as factors deemed significant by NRCS who developed these soil potential ratings. The evaluation criteria are listed in Table 1, 2 – 7 KriteriadalamTabel 1 dirincimenjadibeberapakisarannilai. Nilai-nilaiinimenentukankelas-kelaspotensialtanah. Nilai-nilaiuntukmenentukan “Kelas Rating” dipilihberdasarkantigapertimbangan: Apakah data sesuaidenganregulasikesehatansetempat? Dapatkahinformasidiperolehdari data surveitanahyagada? Apakahnilai-nilaiinimengidentifikasiperbedaanbiayaygsignifikanuntukbiayainstalasi SSDS yang memenuhibakumutu?

24. SPR: Soil Potential Ratings Lima KriteriaEvaluasiadalah: KEMIRINGAN Slope merupakaninklinasipermukaanlahandarigarishorisontal. Percentage of slope is the vertical distance divided by the horizontal distance, multiplied by 100. Thus, a slope of 20 percent is a drop of 20 feet in 100 feet of horizontal distance.

25. SPR: Soil Potential Ratings LAJU PERKOLASI TANAH Ujiperkolasidilakukanuntukmengukurkecepatantanah (jenuh) menyerap air (termasuk air limbah). Pengukurankonduktivitashidraulikdilakukandalammenit per inchidandisebutlaju-perkolasi. Nilai-nilailajuinidipakaidalamsistem “CT Public Health Code”. The percolation rate is not a measure of any one property of the soil. Instead, it is related to many factors including soil texture, kinds of clay minerals, bulk density, structure, size and configuration of pores, number and size of rock fragments, depth to water table, antecedent moisture conditions, chemical composition, etc.

26. SPR: Soil Potential Ratings LAJU PERKOLASI TANAH Soil surveys generally measure saturated hydraulic conductivity (Ksat) to convey the rate of water movement through the soil under (field) saturated conditions as the preferred parameter in the National Cooperative Soil Survey. Percolation rates have also been used to express water flow through soils, particularly for soil interpretations for septic drain fields. For this planning document, percolation rates were estimated for soil types based on saturated hydraulic conductivity values (Table 4). Although these two parameters are different, determined by different methods, and yield different results, they can be considered to be functionally equivalent for this application. Consequently, percolation rates may, with prudence, be used as a proxy for Ksat in this case.

27. SPR: Soil Potential Ratings Lima KriteriaEvaluasi : KedalamanMuka-Air-Tanah Tinggi (Musiman) This is the depth from the soil surface to a zone of saturation at the highest average level during the (SHWT) – wettest season. The depth to a water table is determined primarily through the presence of rustcolored and/or gray soil redoximorphic features.

28. SPR: Soil Potential Ratings The five evaluation criteria are: BANJIR Flooding is the temporary covering of the soil surface by floodwater from streams overflowing their banks, inflow from high tides, or any other combination of sources. The frequency or how often, typically, that it floods is an estimate of the current condition, whether natural or human-influenced (such as dams or levees).

29. SPR: Soil Potential Ratings KEDALAMAN BATUAN INDUK KERAS Depth to bedrock is the depth from the soil surface to the contact with coherent (continuous) bedrock. Ledge rock is another term used for bedrock by the Connecticut Public Health Code.

30. SPR: Soil Potential Ratings PenilaianPotensi Tanah menurutSatuanPeta Connecticut’s statewide soil survey identifies and displays the dominant soils in the state. The symbols on the maps identify map units, each map unit representing a unique combination of soils. Areas within the same symbol have similar composition. The soils were mapped at a scale of 1:12000 with a minimum size delineation of approximately 3 acres. Maps enlarged from the soil survey report do not provide more detailed soils information. More detailed information can only be obtained through on-site investigations. The soil survey is not a replacement for on-site investigation. The survey identifies the probability of finding a particular soil or combination of soils. Table 8 assigns a potential rating to each map unit. The list of map units is in order by soil map unit symbol. The potential rating is based on the ease of installing a SSDS in the dominant soil(s) of the map unit.

31. SPR: Soil Potential Ratings SPR menurutSatuanPeta The majority of map units are composed of one dominant soil or of several soils with similar characteristics. A single potential rating is listed for each map unit. Other map units are composed of two kinds of contrasting soils. In these cases, an overall potential rating is listed for the map unit. The limiting soil characteristics for each map unit are identified in Table 8 under the column labeled Concerns. The table also identifies state regulations which may be applicable if particular soil features are present on the site. This information is located in the column labeled State Regs. The numbers in this column reference the footnotes provided at the end of the table.

32. SPR: Soil Potential Ratings TindakanKoreksi (Perbaikan) Corrective measures are any design or construction practices that may be required on a site. The kinds of measures identified are dependent on the limiting soil characteristics and are commonly used solutions for dealing with those soil limitations. Some soil limitations have no practical corrective measure identified in the CT Public Health Code. Without an on-site investigation, it is impossible to predict exactly what improvements a site will need in order for the subsurface sewage disposal system to work.

33. SPR: Soil Potential Ratings The site improvements are divided into two categories: Probable Corrective Measures –These are on-site improvements that are most likely to be needed on a site having a particular kind of soil. Possible Additional Corrective Measures – These improvements may be necessary on some sites. Whether they are needed depends on the degree of the limiting soil and site characteristics.

34. SPR: Soil Potential Ratings Tindakanperbaikan yang lazimdisarankandisajikanpadaTabel 2, 3 danTabel 5 hingga 7. Kolom “Concerns” menyatakanmengapatindakanperbaikandiperlukandilokasiygmempunyaisifat-sifattanah yang khusus. The tables also identify the state regulations that may be applicable if a particular soil feature is present on a site. This information is located in the column labeled State Regs. The numbers in this column reference footnotes provided at the end of the each table. Kolom “Other Considerations” menyajikanpraktek-praktekataupersyaratanlokasiygdiperlukanuntukmembuat SSDS. Saranainidiperlukanuntukmemungkinkaninstalasisistematauuntukmenentukansolusiyg paling praktisuntukmenjawabmasalahtanahataumasalahlokasi.

35. SPR: Soil Potential Ratings Some Site Conditions and Design Considerations Not Represented in the Ratings Penilaianpotensialtanahuntuk SSDS ditentukanberdasarkankemudahanmengatasipembatas-pembatastanah yang disajiakandalam Table 1. In many cases, the ease of constructing a system and cost is determined by other factors that may be site specific or result from local town requirements.

36. SPR: Soil Potential Ratings A partial list of these factors that may influence cost, but are not represented in the rating scheme, follows: Small areas of contrasting soils too small to delineate at the scale of the Soil Survey of the State of Connecticut. Boulders that cannot be moved by customary construction equipment. Topographic configuration of the property. Fill needed to compensate for the volume of material lost through the removal of stones and boulders. Measuring depth to water table during the spring months. Local health department practices. Inland wetland setbacks. Time needed for approvals from regulatory agencies. Easements. Access to site for testing, construction, and system maintenance. Landscaping. Maneuvering around site features to be preserved such as stonewalls and trees. Tree and stump removal. Hauling costs of fill and gravel. Proximity of proposed leaching field to neighboring wells. Time of year of construction. Construction stakeout and supervision by an engineer or sanitarian.

37. SPR: Soil Potential Ratings Table 1. Evaluation Factors

38. SPR: Soil Potential Ratings Table 2. Corrective Measures for Slope

39. Table 3. Corrective Measures for Soil Percolation Rates

40. SPR: Soil Potential Ratings Table 4. Saturated Hydraulic Conductivity and Percolation Rate*** ***Adapted from the State of Virginia, Virginia Department of Health, September 20, 2001, Footprint Committee Meeting. See references at the end of this document.

41. Table 5. Corrective Measures for Depth to Seasonal High Water Table

42. Table 6. Corrective Measures for Flooding

43. Table 7. Corrective Measures for Depth to Bedrock

44. Table 8. Soil Potential Ratings for Subsurface Sewage Disposal System by Map Unit

45. Table 9. Map Units Grouped by Potential Rating

46. Table 9. Map Units Grouped by Potential Rating

47. Table 9. Map Units Grouped by Potential Rating

48. Table 9. Map Units Grouped by Potential Rating

49. Table 9. Map Units Grouped by Potential Rating

50. Table 9. Map Units Grouped by Potential Rating